Product Review: Eschenbach Club 8 x 20 Pocket Binocular.

The Eschenbach Club 8 x 20 pocket binocular and leather pouch.


A Work Commenced October 9 2022


Product: Eschenbach Optik Club 8 x 20

Country of Manufacture: Unknown

Exit Pupil: 2.5mm

Field of View: 119m@1000m(6.8 angular degrees)

Eye relief: 16mm

Coatings: Fully multicoated, phase correction coating on BAK4 roof prisms

Close Focus: 1.6m advertised, 3.0m measured

ED glass: No

Waterproof: Yes

Nitrogen Purged: Yes

Tripod Mountable: No

Weight: 220g advertised, 220g measured

Accessories: High quality leather storage pouch, lens cleaning cloth, lanyard, eyepiece and objective lens caps, instruction manual 

Warranty: 5 years

Price UK: £149.00


Eschenbach Optik, based in Nuremberg, Germany, is not a name that crossed my radar in my tour of the binocular market. But while reading an online birding forum, I came across some comments and a few pictures of an intriguing pocket binocular marketed by Eschenbach; the Club 8 x 20. It looked rather stylish, somewhat resembling the gorgeous little Leica pocket glasses discussed in some of my earlier reviews. Curiosity got the better of me, so I decided to order one up for closer inspection and testing. What to expect? An opto-mechanical gem or muton dressed as lamb?

I was surprised to learn that Eschenbach Optik was founded over a century ago, in 1913 to be precise, and is a manufacturer and distributor of optical instruments, but is perhaps best known for the manufacture of spectacle frames. Currently they have a work force of nearly 300 people and have a business volume worth about 70 million Euro annually. Eschenbach, I discovered, also sell a comprehensive range of binoculars – most likely imports – in all the popular sizes.

When the binocular arrived, I was pleasantly surprised by the packaging. I received a lovely sliding hard case. A rather fetching leather pouch with the Eschenbach brand name on the front houses the little Club 8 x 20. The package also included a neck strap, a bright blue lens cleaning cloth, instruction manual and presentation card summarizing the features of the instrument in a number of languages. I was surprised to see that the binocular came with both ocular and objective lens caps, something you don’t encounter too often on many of the higher end pocket glasses in my experience.

The packaging makes a great first impression.

The Club is certainly a cute looking instrument; weighing just 220g, it has a double hinge design with a large central bridge. The silver-coloured focus wheel is located at the far end of the bridge, while the dioptre adjustment is accessed by a small wheel built into the eye piece end of the bridge.

The Eschenbach pocket glass unfolded.

I was happy to see some plus and minus markings on it to give the user some basic information about which way to turn it in order to get to your desired setting quickly.

The Club 8 x 20 has a nicely designed dioptre adjuster built into the bridge near the eyepieces.

The barrels are lightly armoured with a finely textured leatherette substrate that gives the instrument quite a retro look, reminiscent of that seen on the Leica Ultravid BL pocket glasses, with delicate contouring of the ocular and objective ends of the binocular.

The underside of the binocular showing the main specs of the instrument. Note the textured leatherette armouring on the barrels.

The chassis appears to be made entirely from nicely machined aluminium. The tiny Club 8 x 20 measures only 10cm long and folds down to a width of just over 6cm, so comfortably fitting in the palm of your hand.

I absolutely love the twist up eye cups on the Eschenbach Club 8 x 20. They are beautifully engineered and remind me very much of those found on the Swarovski’s newest wonder glass, the CL Curio 7 x 21( and the CL pockets as far as I remember). They glide effortlessly and hold their positions very well.

The eyecups are a real class act; turning smoothly upwards to their fixed position.


Eye relief is good, but not outstanding. I was able to see the entire field wearing eyeglasses but some will find it fairly tight. The objectives lenses are nicely recessed – surely a good thing – to cut down on intrusions from rain, dust and peripheral light. The anti-reflection coatings on the lenses are smooth and evenly applied giving a green or purple tint depending on the viewing angle.

Coatings on the ocular lenses.

Nicely recessed objectives.

The aluminium focus wheel on the Club 8 x 20 is nicely textured for good gripping even while wearing gloves. It moves smoothly in both directions without any slippage or free play.

I wasn’t able to find where the instrument was made, although the underside of the bridge displays the main optical specifications. If I’m guessing, it was probably made in China. The instrument is waterproof, and nitrogen purged, making it more useable in wet weather than the Leica Trinovid BCA models, for example, which are only ‘splashproof’, at least in theory.

Moving on to optics, the instrument arrived perfectly collimated.  The BAK4 roof prisms are phase coated and possibly silvered or aluminised. I say ‘possibly’ because the information is not available anywhere in the instruction manual or on their website. I did note that their higher priced Trophy F 8 x 25 ED model has dielectric coatings though, so having a lower reflectivity metal coating seems like a good bet.

Performing my torch test, I picked up some internal reflections and diffused light around a bright light source. The Zeiss Terra ED 8 x 25 tested in the same way had much more subdued reflections, no diffused light, but had a more prominent diffraction spike. Judging by what I had seen before, I would say that these results with the Eschenbach Club 8 x 20 were more in keeping with pocket binoculars offered at around the £100 mark, rather than the £149 I paid for it.

Taking a look at the exit pupils, I was relieved to see that both presented as round, with little in the way of light leaks around them. Good job!

Left exit pupil.

Right exit pupil.

The daylight images served up by the Eschenbach Club 8 x 20 are quite good. The sweet spot is located in the central 50 per cent of the field, with field curvature creeping in and increasing steadily as one looks towards the field stops. Contrast and sharpness are good and glare is kept under very good control for a pocket binocular. I was quite surprised to measure the close focus on my sample of the Eschenbach Club 8 x 20 to be 3 metres and not the 1.6m advertised on their website. Comparing it in side-by-side tests with the Zeiss Terra ED 8 x 25, which has the same 6.8 degree field of view, I was immediately able to see that it was noticeably brighter, a little sharper over a larger field area and had better contrast than the Club 8 x 20. I also detected a slight yellow tint to the Club compared with the more neutral colours served up by the Zeiss. Colour fringing is well controlled in the Eschenbach within the sweet spot but does begin to show on higher contrast targets as they are examined near the field stops. Again, the little Zeiss did better in this regard. Curiously, while displaying the same field of view, I came away with the strong impression that the Zeiss glass was wider.

Size comparison: Eschenbach Club 8 x 20(left) and Zeiss Terra ED 8 x 25(right).

It was only after I looked at a waxing gibbous Moon on the evening of October 8, that I could begin to offer an explanation for my daytime perceptions. Comparing the Zeiss with the Club 8 x 20, I noticed that the sweet spot was considerably larger in the former, with the Moon remaining acceptably sharp nearly all the way across the field. The Eschenbach Club pocket glass threw up a good image of the Moon in the central 50 per cent of the field, but quickly became blurred as it was placed outside its sweet spot. I confirmed that the predominant aberration was field curvature, since I was easily able to focus it out as the Moon’s silvery orb was brought near to the edge of the field.   So I think that my perceptions of the Zeiss having a wider field lies entirely with the fact that it just has a much larger area of its field inside which objects look very sharp. I got broadly similar results when I looked at the bright star, Capella. The image remained pinpoint sharp in the inner 50 cent of the field but as I moved it outside this area, the image of yellow Capella started to show the effects of defocus owing to field curvature. In the outer 15 per cent of the field, the star had bloated to an unpleasant defocused disk.

The Club also threw up a few stronger internal reflections on the Moon than the Zeiss Terra ED 8 x 25. Indeed, despite the Zeiss showing a strong diffraction spike when turned to a bright streetlamp, it wasn’t all that prominent on the bright full Moon observed on the evening of October 9.

Pocket–sized fun.

In conclusion, the little Eschenbach Club 8 x 20 has lots of nice, elegant ergonomic features usually reserved for higher-end pocket binoculars, such as excellent eyecups, a smooth focusing wheel and a well-made dioptre system, not to mention the high-quality leather storage pouch it comes in. It’s a true pocket binocular with its folding hinges. Optically though, it behaves more like models I’ve tested costing about £100, which is probably adequate for lots of people, but for those who believe they are getting something that rivals a Leica or a Swarovski, you might be a little underwhelmed.


Neil English has cultivated a fondness for pocket binoculars. If you like his work, why not buy one of his books on telescopes and the history of astronomy?


De Fideli.

Zeiss Terra ED Pocket 8 x 25 Redux.


Zeiss Terra ED Pocket 8 x 25(China) Package.

A Work Commenced October 1 2022



When the Zeiss Terra ED pockets were first launched, many enthusiasts were pleased to learn that they were manufactured in Japan, but as of 2020, Zeiss moved the production of these units to China, where all of the larger Terra ED models continue to be made. At first, it was the source of some confusion, with some folk chiming in to inform me that their new Terra pockets were marked “Japan,” while others showed pictures of “China” under the bridge. When I made some enquiries, I was first told by one Zeiss employee that they were still being made in Japan, but shortly thereafter they backpedalled, informing me by phone that the new Terra pocket glasses were now being made in China, leaving only their flagship Victory pockets in Japanese production.

A solidly constructed instrument, just like the Japanese-derived model.

Over the last few years, I bought in, tested and evaluated many pocket binoculars from many manufacturers, and inevitably, the build up of equipment in my house meant that I had to gift many of them to friends or sell them on – and that included my Japanese-made Zeiss Terra ED 8 x 25. But after owning and using some top pocket binoculars from Leica, including the 8 x 20 and 10 x 25 BCA models and the Ultravid 8 x 20, I gradually came to accept their limitations, as charming as they are, especially when I began to explore the larger format 8 x 30 and 8 x 32 models. The latter were simply much more comfortable and easier to use, with their bigger eye box and more comfortable handling. And as for optical versatility, the larger 30-32mm formats were in a completely different league to any pocket glass, however sophisticated. A week using my superlative Nikon E II 8 x 30 – my favourite binocular by a country mile – finally convinced me to sell off my little Ultravid 8 x 20 to help recoup some funds(I’m not a collector but an observer), but it did leave a small hole in my modest stable of instruments. I still yearned for a good quality pocket binocular for occasional use, for trips to the theatre and galleries, for travel and exploring interesting buildings in the towns and cities of Scotland and further afield. What to do? It was at this time that I thought I would give the little Terra pocket a second chance, noting that it was still selling at about the same price I paid for my first Terra – £270 – so I took the plunge and ordered a unit up from Cameracentre UK in South Wales.

The China label on view under the bridge.

When it arrived, I was pleased to see that the instrument was presented in the same presentation box my first Terra pocket came in; a sturdy fold-out arrangement, with a lovely presentation of an alpine nature scene. I was equally delighted to see that the binocular was stored inside the same hard, zip-fastened clamshell case, with a magnetic latch to boot. This was a very pleasant surprise, as a 10 x 25 Terra ED model(with a new black chassis) I bought off Amazon in 2021 only came with a soft pouch – hardly enough protection for the instrument, which I returned after not being entirely happy with its optical performance.

A closer look at the large ocular lenses on the Zeiss Terra ED 8 x 25.

The exact same strap was supplied with this new Zeiss Terra ED 8 x 25 too; another good thing, as it is of high quality and perfectly designed to support this small pocket glass(310g). Examining the instrument, I was pleased to see what I had previously observed with my Japanese-made unit. Well put together, with the same grey-black chassis as before. I liked that colour scheme, with the blue Zeiss logo located just ahead of the central focus wheel. I was relieved to see that the double hinge was tight, maybe not as tight as I recall on the Japanese unit, but tight enough. The same immaculate Zeiss multi-coatings were smoothly applied to the ocular and objective lenses, and applying a breath test on a cool, afternoon outdoors, showed that the company’s proprietary LotuTec hydrophobic coatings rapidly dispersed the condensation. Neat!

The wonderful coatings applied to the deeply recessed objectives.

The twist-up eye cups were also working perfectly, rigidly staying in position once clicked into their grooves. The dioptre adjuster – a small wheel located at the far end of the wide bridge – moved smoothly – and once adjusted, I was ready to test the optics.

Beginning with my flashlight test, I directed the light from my Iphone torch adjusted to its brightest setting into the binocular from across my living room to examine the focused image. As I noted with my Japanese model, the results showed very good suppression of internal reflections and very little diffused light around the intensely bright beam but, as before, it did show up a prominent diffraction spike, which was also unfortunately picked up by looking at some streetlamps after dark. No difference between the Japanese and Chinese-made instruments in this capacity. The little Leica glasses were much better in this regard, showing very little of diffraction spikes in comparison.

I never conducted an examination of the exit pupils on my first Terra ED pocket, so was keen to see how they fared in this unit. I’m pleased to report that the results were very good, as you can see below; both pupils presented as perfect circles, with no significant light leaks around them. Bravo!

Left exit pupil.

Right exit pupil

But things turned out even more swimmingly as I began to study the images in bright autumnal sunlight. The view was excellent; bright, sharp, lovely contrast and vivid colours – all the things I had admired in the Japanese-made unit. That’s a consequence of the Schott ED glass used in the objectives and dielectrically coated Schmidt-Pechan prisms delivering an impressive light transmission of 88 per cent. The sweet spot is very large, with only a small amount of softening near the field stops. The view is wide – 119m at 1000m(6.8 angular degrees) – better than on my Leica pockets. I judged the Terra ED’s glare suppression abilities to be very good too – significantly better than my Leica’s, as I remember, with veiling glare being especially well controlled – for a pocket glass at least. The deeply recessed objectives and highly efficient coatings applied throughout the optical train definitely work together here. The quoted eye relief of 16mm is generous enough to enjoy the entire field using glasses, if that’s your thing. It’s also water and fog proof, making it suitable for the most adverse weather conditions Mother Nature is likely to throw at you.

If I’m being honest, the large focus wheel on the Zeiss Terra ED 8 x 25 was, if anything, a little smoother than on my Ultravid 8 x 20. Just over one full turn clockwise brings you from closest focus(~ 1.9 m)  to beyond infinity. Indeed, the wheel moved further beyond infinity than many other binoculars I’ve tested. Surely that means that with a bit of clever tweaking(which can be done!), the focuser can be re-adjusted to render the close focus even shorter, but that’s for another day.

Comparing the Nikon E II 8 x 30 to the Zeiss Terra ED 8 x 25(right).

In good lighting conditions, and taking into account its considerably smaller field,  the Zeiss Terra pocket throws up very comparable views to my Nikon EII 8 x 30, with broadly similar levels of contrast and sharpness. Colour tone is noticeably warmer in the little Zeiss Terra though, and following the course of a long, straight section of country road, the compact Nikon Porro easily showed greater levels of contouring(stereopsis), as I expected from its more widely spaced objectives. This is a quick and easy way to see the advantages of Porro prism binoculars over their roof prism counterparts. The fact that you can more easily discern the bumps and depressions in the road is proof enough that the Nikon shows more spatial information than the little Zeiss roof prism binocular.

Another significant difference between the models is comfort and ease of viewing; eye placement is a lot more finicky with the Zeiss, requiring the precise alignment of one’s eyes with the barrels, and the smaller exit pupil requires a little more skill to find a satisfactory viewing experience. But a 3.1mm exit pupil is much easier to engage with than the 2.5mm pupils on my Leica glasses. None of this was an issue with the little Nikon 8 x 30 though: you simply bring it to your eyes for instant gratification, and drink up the enormous 8.8 degree field in all its optical glory! Having said all that though, I was very impressed how well the little Terra handled the affair. It’s a pocket binocular after all!

A quality experience.

So, in conclusion, should I be worried about the fact that the new Terra ED pockets are made in China? For me, the answer to that question is definitely no. It’s every bit as good as the Japanese unit I once had. Properly looked after, it ought to give many years of service. After all, it’s still a Zeiss binocular; and you can tell that from the instant you gaze through it!

Happy Camper!


Neil English has tested more pocket binoculars than you could shake a proverbial stick at. Find out more from his up-and-coming book: Choosing & Using Binoculars: A Guide for Stargazers, Birders and Nature Enthusiasts, published by Springer Nature in late 2023.



De Fideli.

Product Review: GPO Passion 8 x 56.

GPO Passion 8 x 56.



A Work Commenced September 23 2022



Product: GPO Passion 8 x 56

Country of Manufacture: China

Chassis: Rubber armoured magnesium alloy

Exit Pupil: 7mm

Eye Relief: 20mm

Field of View: 126m@1000m(7.35 angular degrees)

Close Focus: 2.3m advertised, 2.14m measured

Prism Type: Abbe-Koenig

Coatings: Fully broadband multi-coatings, phase correction coatings on Abbe Koenig prisms

Light Transmission: 92%

ED Glass: No

Waterproof: Yes

Nitrogen Purged: Yes

Weight: 1245g advertised, 1257g measured

Dimensions: 19.2 x 15.8 cm

Accessories: Instruction manual, cleaning cloth, hard, case, neoprene neck strap, hard case strap, objective covers, ocular covers and warranty card.

Warranty(European): 10 Years

Price: UK £589.00


In previous blogs, I reviewed some excellent quality binoculars from the new German-based company, German Precision Optics(GPO). In these reviews I was very impressed with the outstanding build quality of their products, not to mention their excellent optical quality. But GPO have not just settled on securing a solid niche in the compact and mid-sized binocular market, they have also developed larger aperture models specifically designed for low light work and astronomy; enter the GPO Passion 8 x 56 and 10 x 56 series.

I acquired a 8 x 56 unit on loan from Steve at First Light Optics for testing and evaluation, and I must again say how delighted I was to see that GPO really are delivering excellent value for money in this competitive corner of the sports optics market.

The instrument arrived in a beautiful presentation box, as shown in the photo above. The binocular was set rigidly in place in the cut-out foam section and lying adjacent to it, the beautifully designed hard case to store the instrument. Inside the case you’ll find the usual accessories; padded neoprene logoed neck strap, carrying strap for the case, a comprehensive multi-language instruction manual and microfibre lens cleaning cloth. If you take the case out, you’ll also find the 10-year European warranty card for the instrument.


The GPO Passion 8 x 56 is one chunky instrument and you immediately get the feeling of quality the second you prize it from the box. This larger instrument is a scaled up version of the 42mm and 32mm Passion ED binoculars, with a magnesium alloy chassis overlaid by a nicely textured black rubber armouring.

The distinctive curves of Abbe-Koenig optics are abundantly in evidence at first glance.

Tipping the scales at 1257g, this is not an instrument that many would happily trek with all day long; unless you’re Hulk Hogan.

The underside of the GPO Passion 8 x 56. Note the absence of thumb indents which aren’t really necessary anyway.

It’s designed to be used for short hand-held viewing but mostly for tripod mounted activities, such as hunting in low light or watching the stars The focus wheel is covered in a textured black rubber which is easy to grip, rotating just over one full revolution anti-clockwise from nearest focus to just beyond infinity. Though I have reported a small amount of free play in a smaller 10 x 32 GPO Passion ED in a previous review, I was pleased to see that there was none apparent on the focus wheel of this 8 x 56 model.

The beautifully machined aluminium twist-up eyecups are amongst the best in the industry.

A closer inspection of the shape of the barrels betrays the nature of the prisms used in this binocular; the large Abbe-Koenig roof prisms that deliver higher levels of light than standard Schmidt-Pechan prisms incorporated into the smaller GPO models. It’s these Abbe-Koenig prisms that contribute to the weight and the length of this binocular, but it’s all the more remarkable that this optical design is incorporated into this low light binocular at this price point. These prisms are notoriously difficult to make well and are usually only found in instruments costing at least twice as much as this 8 x 56 costs.

The beautifully machined twist-up aluminium eye cups are covered in soft rubber for very comfortable viewing. Four positions are offered to suit most anyone’s requirement for eye relief. I’ve said it before and I’ll say it again: these are amongst the best eye cups ever designed by any binocular manufacturer, period. I was easily able to access the entire field of view with eyeglasses, so absolutely no worries there. The dioptre adjustment is accessed by turning a ring under the right ocular. It moves smoothly but with considerable tension, ensuring it won’t easily be moved out of position in field use.

The proprietary broadband multi-coatings present with a fetching purple hue in broad daylight and are immaculately applied. Viewed head on, they make the lenses almost disappear. The instrument is dry nitrogen purged internally and o ring sealed to prevent fogging up of the internalized optics. It’ s also waterproof, but GPO don’t mention to what degree it will withstand water immersion.

The view of the ocular lenses and focus wheel from above. Check out the beautifully applied antireflection coatings as seen in broad daylight.

The reader may be surprised to learn that, unlike the smaller ED models, the larger 8x and 10 x 56 models do not contain ED glass. GPO believe it wasn’t necessary to incorporate extra low dispersion glass in these models because their main use was in low light conditions, when seeing any colour in a given target becomes difficult to discern, so there would be little advantage in employing an ED element which would have significantly increased its production cost. Having enjoyed many hours testing the instrument both in low light situations and under the stars at night, I can only agree with their design philosophy, as I shall report on a little later. All in all, the build quality and ergonomics of this 8 x 56 are exemplary, and quite in keeping with the other models I’ve reviewed from both their ED and HD lines in the past.

The large objective lenses on the GPO Passion 8 x 56; note how the glass almost disappears when viewed from certain angles.

Optical Testing

My first optical test involved shining a bright light source into the binocular and examining the images produced. I detected a few minor reflections but nothing too intrusive. Diffraction spikes were very subdued and there was very little in the way of diffused light around the light source, indicative of good, homogenous glass. Turning the binocular on a bright streetlamp after dark did show a few minor internal reflections as I anticipated, but by and large I was quite happy with the result. Placing the lamp just outside the field of view showed very little in the way of stray light intrusion; an impressive result compared with many other similar tests performed on other binoculars.

Examining the exit pupils also yielded good results, as shown below. The large 7mm exit pupils were perfectly round with little in the way of extraneous light around them. I did pick up some light leaks well away from the pupils though, a consequence of using Abbe Koenig prisms perhaps? Thankfully they appeared to make no material difference to the images garnered by the instrument, in daylight at least.

Left exit pupil.

Right exit pupil: note the arc of light away from the pupil at lower right.

Testing the binocular out on a bright, sunny afternoon revealed very impressive images right from the get-go. The view is razor sharp inside its very large sweet spot, with only a small amount of softening of the images noted near the field stops. Contrast is excellent.  Scanning a large swathe of trees at the edge of a forest proved to be a very comfortable experience and extremely easy on the eyes, with no blackouts or the rolling ball effect, kept under control courtesy of a modest amount of pincushion distortion near the field stops. Colours are very vibrant in this big glass and I immediately noted the warm tone of the images – very much like those I reported on the smaller ED and HD models. Indeed, I had long wondered whether this warm colour tone was a manifestation of the ED glass utilised in the smaller GPO binoculars or just from the coatings used. I now think it has more to do with the latter than the former.

Glare suppression is excellent in the GPO Passion 8 x 56. It stubbornly refused to show any on bright autumnal days, and also on grey overcast days in the open air. Veiling glare was also exceptionally well suppressed in this instrument too; a testament to the excellent coatings applied to the lenses and prisms, as well as the baffling used throughout the optical train. Close focus was also very surprising. I measured it at just 2.14m, so slightly better than the advertised 2.3m. I consider that amazing for such a large glass!  Chromatic aberration was also very well controlled in this unit. There is a small amount visible on high contrast targets, such as imaging the side of a telephone pole against a bright overcast sky. Lateral (off axis) colour is a bit more pronounced in this large aperture instrument though, as I openly expected, but I felt it was perfectly acceptable given the modest price tag of this instrument. Overall, I would rate the daytime images as quite excellent.

Testing its low light capability, I compared and contrasted it with the views through my excellent Opticron Imagic TGA WP 10 x 50 Porro prism binocular. I found the views very comparable until about a half hour before sunset on September evenings, with the 8 x 56 pulling noticeably ahead on selected targets under poorly illuminated hedgerows as the last rays of sunlight dipped below the horizon. By about a 40 minutes after sunset, the 10 x 50 was really struggling in comparison with the 8 x 56.

Under the Stars

I was dying to find out how the GPO Passion 8 x 56 would perform under a dark, clear sky at night, and I wasn’t disappointed here also! In fact, the views were absolutely stunning! The very generous field of view effortlessly frames wonderful star fields. Bright stars such as Vega and Aldebaran are rendered in their natural colours. Chromatic aberration was a non-issue in the inner 50 per cent of the field, and only showing mild splashes of bluish purple as the stars were moved to the outer part of the impressively large field of view. Fainter stars were examined to see how well they maintained their pinpoint sharpness. I was very pleased to see that they remained impressively small and tight across about 75 per cent of the field, with some mild field curvature beginning to show up thereafter. Only in the last 10 per cent of the viewing portal, could I make out  a small amount of astigmatism and coma creeping in.

I was genuinely surprised how long I could hand hold the binocular while scanning the Milky Way through Cygnus, Perseus and Cassiopeia. The low power of 8x definitely helps in this regard. For more serious studies though, I resorted to mounting the instrument on a light weight monopod. Views of the Pleiades and Hyades in Taurus were simply stunning, its impressively high light throughput presenting very faint stars quite invisible to a 42mm model. In fact, this instrument threw up some of the best binocular views of the heavens I have personally experienced. I enjoyed exploring many early autumn open clusters, such as the M36, 37 and 38 spanning the mid-section of Auriga. M 34 in Perseus and the great globular cluster in Hercules (M13) in this large binocular light bucket. Mighty Jupiter, now prominent in our night skies, was dazzlingly bright, with its four giant moons being easily seen. Fiery red Mars was also stunningly presented in Taurus against a jet black sky.  The Alpha Persei Association and Double Cluster in Perseus were breath-taking in this binocular too. Rising up in the wee small hours of late September, I was treated to some extraordinary views of Orion; with the white and blue-white Belt stars shining brilliantly, and below them, the famous Sword Handle of the celestial Hunter, with the magnificent Orion Nebula blazing forth across the light years. The excellent light gathering power of the GPO 8 x 56 allowed me to follow much fainter tendrils of nebulosity than I could make out in a optically excellent 7x 50 Porro prism binocular, though I must concede to yearning at times for a look through its higher power sibling; the 10 x 56, which probably would have totally blown me away lol. All of these experiences only consolidated what I had seen during the day: this is an excellent low light/astronomy binocular that would satisfy the most discriminating of observers.

Bon Voyage!

So, here we have yet another GPO binocular offering exceptional ergonomics and really good optics for a very decent price. I say this in light of a cursory examination of other 8x or 10 x 56 models, built around Abbe-Koenig prisms. The Zeiss Conquest HD 8 x 56, for example, has a build quality quite comparable to the GPO Passion, but its field of view is slightly smaller(125m@1000m), its weight slightly heavier(1265g),  its eye relief lower(18mm), its close focus distance much longer(3.5m), and possesses a light transmission of 90 per cent, lower than that of the GPO Passion, even with ED glass. But that instrument retails for more than twice the price of the big GPO light bucket! Or consider the fluorite containing Maven B5 10 x 56 costing a few hundred pounds more than even the Zeiss Conquest HD but with the same light transmission as the GPO Passion(92 per cent or so). Seen in this light, the GPO Passion 8 x 56 offers tremendous bang for buck and absolutely deserves great success in the burgeoning sports optics market.


Highly Recommended!



Dr Neil English explores many more hot bargains in his up-and-coming book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Nature Enthusiasts, due out in late 2023. 

My sincere thanks to Steve at First Light Optics for kindly lending me the instrument for field testing.



De Fideli.

Evaluating a Classic Nikon E 10 x 35.

The Nikon E 10 x 35.

A Work Commenced September 7 2022.



If you’ve been following my blog reviews, you’ll be aware of my great affection for the Nikon E II 8 x 30. From the moment I put it to my eyes, I was stunned by the magnificent views it served up: a wonderful, tack sharp, ultra-wide view, rich in contrast and detail, and all with an enchanting 3-dimensionality. That experience got me curious about other small Nikon Porros and I became intensely interested in the now discontinued E series, especially after reading Roger Vine’s glowing report on the Nikon E 8 x 30 linked to in the preamble above. I decided to bite the bullet and purchased a used Nikon E 10 x 35 from a seller based in Tokyo, Japan.

The workmanship that went into the making of the Nikon E 10 x 35 is exemplary.

The seller stated that the instrument was in good condition, with no fungus and a small amount of dust that had made its way inside the instrument. Checking the serial number, I was relieved to see that it was one of the later, multi-coated models, which were manufactured between 1988 and 1998, after which time Nikon introduced their latest, greatest small Porros – the venerable E IIs and SEs. Judging by the numbering – 611675 – I guessed that it was made in the mid -1990s.

The serial number most likely dates this instrument to the mid 1990s.

It took just a week for it to travel from the Far East to my home here in rural central Scotland, and I was very excited about the prospects of holding the instrument in my hands. The binocular was exceptionally well packed, taking what I felt was an eternity to remove all the bubble wrap before I could finally hold it! Straight from the get-go I was extremely impressed with the instrument, coming only with a neck strap of extremely high quality. The instrument looked very lightly used, with no significant scuff marks on the body. I could instantly tell that this instrument was made during an era where craftmanship was at a much higher level than it is today; the beautiful contouring of the solid metal chassis, overlaid by an immaculately applied retro leatherette armouring. As Mr Vine states, you simply don’t get instruments made to these standards today!

The underside of the binocular.

Weighing just 624g without its strap, the instrument feels great in the hands. Like the newer E II models, the eyepieces are fitted with soft rubber and offers decent eye relief for eyeglass wearers. Texture-wise they felt just as firm as the E II, which came as a relief to me, as I had heard that this type of rubber hardens with age. The focus wheel is slightly less refined than on the E II though, feeling significantly stiffer to turn. The opposite was true when I examined the dioptre adjustment mechanism, located under the right ocular. It was significantly easier to move then the E II dioptre ring, but still stiff enough to remain in place firmly during field use.

The objective lenses looked immaculate, with the characteristic green coatings. Ditto for the ocular lenses.

The multicoated objectives are in pristine condition.

View from the ocular end of the instrument.

I was relieved to see that the instrument arrived in excellent collimation. The exit pupils were nice and round, with very little extraneous light around them. Performing my Iphone torch test showed no significant internal reflections, diffused light or diffraction spikes, all characteristic of a well-executed Porro prism design. But I hit a snag when I examined the interior of the binocular from the objective end. Yes, there was a small amount of dust visible on the prisms, a very thin veneer of haze, but also significant fungal growth on the prisms of both barrels – something I was assured was not present by the Tokyo seller.

Saprophytic wee blighters. Top centre. Some haze present also.


Left exit pupil.

Right exit pupil.

Fortunately, the fungal growth and dust didn’t significantly compromise the view. How was it? Well, I can agree with Mr. Vine about its sheer superiority to the classic Zeiss 8 x 30s. Compared with my late 1980s multicoated Zeiss Jenoptem 8 x 30, the Nikon view was indeed much better. 10x in a very well corrected 6.6 degree field offers a unique perspective; at least from my own experiences. Brightness, contrast, glare suppression and sharpness were all very good in this modern classic. And just like my smaller E II, the view is supremely comfortable, with no problems with eye placement and zero issues with blackouts. I disagree with Mr Vine’s claim of 90 per cent transmission though. Maybe at yellow-green wavelengths, but surely not over the entire visible spectrum.

I also disagree with Mr. Vine regarding the ultimate quality of the view; comparing the images of the Nikon E II 8 x 30 to the E 10 x 35, I judged the former superior in terms of contrast and glare suppression. I also compared it to my excellent Opticron Imagic TGA WP 10 x 50, which served up a noticeably brighter and maybe even a tad sharper image, with much better glare suppression and noticeably more vibrant colour renditions. I know this was not a totally fair comparison, as there is a world of difference between a 10 x 50 and a 10 x 35. In bright sunny conditions, the views were quite comparable, but under overcast skies, the 10 x 50 pulled far ahead of it.

A properly executed modern Porro prism binocular can edge out even the greatest of classics. Opticron Imagic TGA WP 10 x 50(left) and the Nikon E 10 x 35(right).

This came somewhat as a shock to me, but in retrospect, modern anti-reflection coatings are just superior to older ones, and there’s no getting around that. The world has moved on. Mr. Vine also stated that to get images in the same league as the E series, you’d have to move to the Swarovski Habicht, Nikon E II or SE series. My comparisons of the Nikon E 10 x 35 with the Opticron Imagic TGA WP proved otherwise.

A Great Night Under the Stars

In the wee small hours of the morning of September 6, I enjoyed sumptuous views of the Hyades in Taurus and right above it, fiery red Mars and the Pleiades. 10x has  been my personal favourite magnification for stargazing of late. It just goes that little bit deeper than a 8x equivalent. I was very impressed by the Nikon E 10 x 35’s wide field of view, with pinpoint stars across most of the field. Near the field stops, you can readily make out some field curvature, which can be focused out to some degree. Moving higher into the sky, the Nikon E served up excellent views of the early autumn Milky Way through Cygnus, Cassiopeia and Perseus. Views of the Double Cluster were also highly captivating, following the curving chain of stars northwards to commune with the lovely starry patch, Stock 2. Later in the season, this will make a nice lightweight binocular to study the winter constellations of Gemini and Orion, both of which are rich in astronomical booty.

Notes form the Field

At home in nature.

I enjoyed one more day with the Nikon E 10 x 35, taking it up to one of my local patches – Culcreuch Pond – where I enjoyed some great views of Mute Swan cygnets learning how to fly. It’s all about mimicry. The adult directs the cygnets to one end of the pond, then takes to flight, keeping low above the water. The cygnets began flapping their wings frantically but as yet, they’ve not mastered the power of the air. I was also lucky enough to watch a magnificent Red Kite circling over the newly cut hay in a nearby field, the 10x glass showing some nice details quite invisible to a 8x equivalent. Close focus was measured to be 3.7 yards – plenty close enough for the vast majority of birding activities. It was during such a time that I thought about what I’d do about this very good modern classic, and I decided on getting it professionally serviced by skilled experts. I wanted to have the fungus removed from the prisms and the optics thoroughly cleansed so that it would enjoy a new lease of life. So I phoned Tony Kay, technical director of OPTREP, based in Selsey on the south English coast( the home of the late Sir Patrick Moore no less), explaining what work needed done to the instrument and whether he was willing to refurbish it for me. To my relief, he accepted. So I fetched my leatherette pouch that came with my Nikon E II 8 x 30, which proved to be a snug fit for the larger 10 x 35 glass, packing it away in a small box with plenty of bubble wrap. The next day, September 7, it was winging its way to his workshop.

Haste ye back!

Needless to say, I’m very much looking forward to seeing what Tony can do to revitalise the Nikon E 10 x 35. Hopefully, I’ll get it back soon, when I’ll provide an update to this blog.

Update: On Saturday September 24, the instrument arrived back safely from its journey to the English south coast. I’m happy to report that the Nikon E 10 x 35 was thoroughly cleaned internally, with no sign of fungus, haze or dust inside the barrels. Collimation was perfect also. All in all, a very happy camper and excited to begin new adventures with this great classic Porro prism binocular from Japan.

The refurbished Nikon E 10 x 35.

I prepared another ‘sarcophagus’ for this instrument to keep it bone dry and free of internal moisture; just in the same way I store my Nikon E II 8 x 30.

The water and air tight container filled with several silica gel desiccant sachets to maintain a bone dry storing compartment for the instrument.

I’ll have more to say about both these instruments in the coming weeks and months, so watch this space.

Thanks for reading!





De Fideli.

Product Review: Kowa SV II 8 x 32.


The Kowa SV II 8 x 32 package.

A Work Commenced  September 20 2022



Product: Kowa SV II 8 x 32

Country of Manufacture: Japanese designed, assembled in the Philippines

Exit Pupil: 4mm

Eye Relief: 15.5mm

Field of View: 136m@1000m(7.8 angular degrees)

Close Focus: 2m advertised, 1.68m measured

Chassis: Thick rubber armoured polycarbonate

Coatings: Fully Multicoated, phase correction coating on Schmidt Pechan roof prisms, KR hydrophobic and anti-scratch coatings on outer lenses.

ED Glass: No

Waterproof: Yes

Nitrogen Purged: Yes

Tripod Mountable: Yes

Weight: 565g advertised, 563g measured

Accessories: Soft padded case, quality logoed neoprene neck strap, rubber ocular rain guard and plastic lens covers, instruction manual.

Warranty: 10 years

Price UK: £229.00


The Japanese optics company Kowa has earned an excellent reputation among sports optics enthusiasts for over three quarters of a century. Today, they offer an exciting range of binoculars and spotting scopes that constantly push the envelope in ergonomic and optical performance. At the time of writing, Kowa manufacture an impressive array of binoculars to suit most people’s budget, ranging from tiny, pocket-sized binoculars right up to 56mm monsters. The SV series, Kowa’s entry level mid-sized binoculars, were first introduced in 2011, and created quite a splash, with many birders and hunters singing high praises for their innovative design and great optical performance. But in January 2020, Kowa introduced their revamped SV II series, which gives the customer a choice of six models in all – just like the original series  – a 8 x 32, 10 x 32, 8 x 42, 10 x 42 and two 50mm models giving 10x or 12x. I ordered up the 8 x 32 SV II model for testing and evaluation. I’m also delighted to say that it was a very pleasant surprise! To see why, read on!

The Kowa SV II 8x 32 has a very well designed chassis with a distinct ultra-modern accent.


The binocular arrived inside a padded logoed carry case, which in turn was placed inside a small green box. The instrument has a thick green rubber armouring; very reminiscent of the Leica Trinovid HD 8 x 32 I tested in 2021. The chassis is fashioned from a lightweight but tough polycarbonate substrate and has extra rubber padding around the objective lenses to afford them some extra protection from stray light and the elements. The rubber is beautifully textured and very easy to grip but does attract dust rather easily.

Close up of the textured rubber used on the Kowa SV II 8 x 32. Though it grips well, it does attract dust rather easily.

The eyecups on the Kowa SV II 8 x 32 were also a very pleasant surprise. They have four positions in all and lock into each place with a reassuring ‘click’ sound. I’m also happy to report that the eyecups don’t collapse unless a sizeable force is applied to them. Eye relief is tight though: I struggled to see the entire field with my eyeglasses on. Fortunately, that isn’t an issue for me as I don’t wear glasses while using binoculars. The focus wheel is covered in soft rubber with tear shaped indentations very much like those used on Kowa’s YF range of compact Porros. I judged its tension to be excellent – very smooth with no free play and backlash when rotated in either direction. 1.75 revolutions clockwise brings you from closest focus to just beyond infinity.

Close up of the serial number and country of assembly.

The Kowa SV II 8 x 32 feels great in the hands, as it’s so easy to grip and wrap your hands around. Kowa didn’t skimp on the strap either; it was easy to attach and is nicely padded for comfortable transporting. The exterior lenses are treated to Kowa’s proprietary KR coating to repel water, dirt and oily deposits, and helps protect against accidental scratching.

Check out the extra thick padding around the objectives!


There was no cleaning cloth supplied with the instrument however. The ocular rain guard is made from standard rubber, but the objective caps are of the cheap plastic variety. To summarise, I love the thoroughly modern accent of this binocular, which was very thoughtfully designed to be pushed hard in the great outdoors.

Optical testing

I began to test the optics by examining how the instrument handled an intensely bright beam of light from across a room. The results I got were very encouraging. There was very little in the way of internal reflections and ghost images. I did see a weak diffraction spike though, but it was quite subdued compared with other instruments in this price category. There was very little diffused light around the beam, indicating the glass used was of very good quality and of high homogeneity. Later, after dark, I turned the Kowa SV II 8 x 32 on a bright sodium street lamp and, as expected, I got a great result; no ghost images and only the merest trace of a faint diffraction spike. In another test I photographed the light emanating from the exit pupils. The results were excellent as you can see below, with nice dark areas around the perfectly round pupils. So far, so very good!

Left exit pupil.

Right exit pupil.

The view through the Kowa SV II is excellent; very bright, sharp and with really impressive contrast and a lovely hard field stop. Collimation was spot on. The excellent tension on the focus wheel brings the images to a very precise, razor-sharp focus, with absolutely no ambiguity. Colours are vibrant and true to life, presenting with an overall neutral cast to my eyes. The sweet spot is very large, with only the extreme edges of the field showing any significant distortion. This I was able to ascertain by star testing more fully at night. Centring the bright star Vega in the field of view, I was able to monitor how the image changed as it was moved off axis towards the field stops. I was delighted to see that even at the extreme edges, there was only very minor distortion mostly attributed to very mild field curvature. To be honest, I had expected it to fare worse in this regard as the specs of this binocular – 7.8-degree field, 15.5mm eye relief etc – are found on quite a few other models, such as the Svbony SV 202 8 x 32 and the Celestron Trailseeker 8 x 32, for example, each of which had quite blurry images near the field stops, as my notes showed. This Kowa SV II turned out to be in a completely different league in this regard, with a much flatter outer field.

Glare suppression was also in a completely different league to the aforementioned models but I’d also have to include the Vortex Diamondback HDs here too. The excellent coatings and baffling on these Kowa SV IIs made all the difference in aggressively suppressing both general and veiling glare as revealed after extensive field testing. Close focus was measured to be just 1.68m, considerably better than the quoted 2m stated in the accompanying user manual. Blackouts – caused by spherical aberration of the exit pupil – were pretty much non-existent as well. Overall, I found the views extremely relaxing and engaging; a sure indicator of an optically excellent  instrument.

Though the field of view is fine and wide, one gets the impression that it’s wider than it really is owing to the well corrected outer field. Chromatic aberration is very well controlled despite its non-ED labelling. I could detect the merest trace of it in the centre of the field on the highest contrast daytime targets, and an average level of lateral colour as one moves away from the centre to the periphery of the field of view. There is a modest amount of illumination drop off as targets are moved to the edge of the field. This was easily seen by centring the Pleiades in the binocular field and then moving the celebrated asterism to the field stops.

Portable Pleasure.

In conclusion, the Kowa SV II 8 x 32 is an excellent instrument for birdwatching, nature studies and even for enjoying the showpiece objects of the night sky. For its modest retail price it sure punches well above its weight. At the time of writing, I note that its bigger brother; the 8 x 42 is available for a lower price than then 8 x 32 model. That sounds like one heck of a bargain!


Highly recommended!


Dr Neil English is currently writing a comprehensive binocular buyer’s guide. Choosing & Using Binoculars: A Guide for Stargazers, Birders and Nature Enthusiasts hits the bookshelves in late 2023.



De Fideli.

Two Low Light Binoculars Compared: Opticron Imagic TGA WP 7 x 50 vs 10 x 50.

The Opticron Imagic TGA WP 7 x 50 & 10 x 50.

A Work Commenced August 26 2022

Preamble 1

Preamble 2

Preamble 3

Preamble 4


There’s been many highs and lows on my 4-year journey through the wonderful and sometimes weird world of binoculars. Arguably the greatest high for me was my re-discovery of the many charms of Porro prism binoculars. Yet, it’s certainly the case that these instruments have been unfairly demurred for reasons that continue to baffle me. The simple truth is that a well-made Porro prism binocular can produce outstanding images using relatively simple technology compared with roof prism models that never seem to stand still. Almost every other week a new model hits the market promising out-of-this-world performance at out-of-this world price tags. I spent more than three years testing all manner of roof prism instruments without ever giving a thought to the humble Porro prism binocular- apart from the quirky reverse-Porro design of the Pentax Papilio II. Why? I supposed I swallowed hook, line and sinker the urban myth that the latter were simply inferior just because they were cheaper. After all, you get what you pay for, right? I mean, how could a full-featured Porro prism binocular costing a couple of hundred pounds realistically compete with a sexy, streamlined roof prism model costing a cool grand or more? Fortunately, I’ve spent the last six months buying in and testing some really nice Porro prism binoculars, and these collective experiences have consolidated my preference for these over their roof prism counterparts.

And I appear to be in good company.

UK-based Opticron is to be lauded for keeping high quality Porro prism binoculars alive and well in the 21st century. As one of my main birding binoculars, I enjoy the excellent quality views of the now discontinued SR.GA 8 x 32 which delivers very similar though not quite as stellar views to my favourite instrument; the superlative Nikon E II 8 x 30, which I tend to baby just a little owing to its lack of rubber armouring.

But that got me thinking about what higher power instrument to use for the dull days of Winter and/or for longer range work, but most especially as a general purpose astronomical instrument to be used during our long, dark(and often cold) winters  here at 56 degrees north latitude. I had enjoyed a high quality 10 x 32 for a while but it lacked the light gathering power of bigger 10 x 42 models, which I also seriously considered. I had contemplated using the Opticron Adventurer T WP 10 x 42, a larger format Porro, but instead I decided to buy in and test two intriguing 50mm instruments from the same company – the 7 x 50 and 10 x 50 Imagic TGA WP models – to field test and learn as much as I could about them. I’ve been testing both of these instruments in various conditions, by day and by night, both at home here in Scotland, and while on vacation in south Wales, and have been so impressed with them that I decided to hold onto one model – the 10 x 50 – as I now firmly believe that it will do everything a 10 x 42 model can do, only better! To see why, read on!

A Closer Look at the Ergonomics of the Instruments

As outlined in Preamble 1 above, I had previously acquainted myself with the many delightful features of the Opticron Imagic TGA WP in the smaller 8 x 32 format, which is now in the capable hands of a keen lady birder on Jersey, in the Channel Islands. I was delighted to see these larger instruments had precisely the same features. Porro prism binoculars are not generally known to be waterproof, and this is one reason cited by some for rejecting them for serious field use. These instruments are o ring sealed and purged with dry nitrogen gas, so that traditional excuse is no longer valid.

Both 50mm models are waterproof and nitrogen purged.

“I don’t like the old-fashioned rubber eye cups on those classic Porros,” I hear you say.

These Imagic TGA models have fully modernised twist-up eyecups that click solidly into place and hold their positions firmly.

Check out the excellent rubber armouring and solid twist-up eyecups on these 50mm models.

What about eye relief? That’s quite poor in classic Porros isn’t it? Not on these models; the 10 x 50 has 19.5mm of eye relief and the 7 x 50 has a full 21.5mm. That’s ample for any eyeglass wearers. And yes, I’ve tested them both using my own eyeglasses and both present the full field in complete comfort.

“What about the dioptre mechanism? Isn’t that the usual ring under the right ocular?”

No, these models possess an ingenious click-stop mechanism. The ring has an unusually high degree of tension and clicks its way round to your preferred setting. Once there, it clicks into place and doesn’t budge: just as effective as any locking dioptre setting featured on much more expensive roof prism models. What an excellent piece of applied engineering! Incidentally, fellow author, Stephen Tonkin, a highly experienced astronomy binocular enthusiast(see Preamble 2 above), whose opinions I trust, referred to the dioptre as being ‘very stiff.’ That’s true, but he likely under-appreciated this feature for daytime uses, when dioptre settings are more likely to wander.

The right eye dioptre is ingeniously engineered, clicking into place firmly and quite incapable of being accidently moved.

“Oh but Porro prism binoculars are big and clunky right?”

Ah, no, both of these instruments tip the scales at just over 800g. The 7 x 50 weighs 823g, while the 10 x 50 weighs just one gram more. That’s lighter than some of the heavier 42mm roof prism models I’ve tested, and for a 50mm specification, these are reassuringly lightweight.

“Yer but they’re awkward to handle!”

Nope, these instruments are exceptionally easy to handle. The weight is brilliantly balanced in my medium sized hands. Indeed, both instruments rate very highly in terms of pure form factor. They feel great in the hand.

“What about the armouring? I’ve heard this can be a bit skimpy on classic Porro models.”

Maybe on older models, but not on these. Both are endowed with a good, thick, protective rubber armouring, with upraised ridges for exceptional grip, even in wet weather.

“OK, OK, but they just don’t look as cool as roof models.”

Oh please; don’t be so shallow!

Ocular & Objective Lenses

Both instruments are fully multicoated and treated with the company’s proprietary differential  F coat to minimise glare and internal reflections. The objectives are nicely recessed to protect the instrument from rain, dust and stray light. Check it out below:

Nothing shallow about these: the beautifully applied anti-reflection coatings applied to the deeply recessed objective lenses.

The ocular lenses are large and easy to engage with.

The ocular lens with eyecups fully retracted.

There is only one significant physical difference between the two instruments, and it pertains to the size of the eyepiece lenses. The 10 x 50 has a 21mm diameter, while the 7 x 50 lens measures only 18mm.

The ocular lenses are larger(21mm) on the 10 x 50 model, compared with 18mm for the 7 x 50.

The focuser on both instruments is exceptionally smooth and backlash free in either direction: very similar if not identical with my smaller SR.GA. 8 x 32. Tension is perfect for my taste – excellent in fact! It takes just three quarters of one revolution anticlockwise to go from near focus to infinity, and beyond.

Tripod/monopod compatible?

Yep, just unscrew the cap at the head of the bridge, mate it to a good quality tripod/monopod adapter and you’re off to the races!

Both binoculars have a decent IPD range: 57 to 73mm, so even smaller faces can engage with them easily.

What about accessories?

Well, you get a basic but perfectly functional rain guard that can be attached to the strap if you like it that way. I don’t like any appendage hanging from my optics so I usually carry it in my jacket or trouser pocket if its raining or threatening to do so. The objective caps are basic plastic covers but they fit tightly.

The carry case accompanying both instruments is well made from faux leather. It is lined internally and has enough space to carry the binocular with its strap attached

Both instruments come with a very nicely designed case which very adequately protects your investment.

The instruments fit snugly inside the supplied carry case, even with the strap attached.


Optical Assessment: 

I measured the effective aperture of both instruments simply by shining a bright light through the ocular lenses and measuring the size of the circle of light projected on a flat surface. Both showed no evidence of stopped down optics with effective apertures of  about 49mm for both the 7x and 10x instruments.

Next I examined the exit pupils of both instruments. Both delivered satisfactory results. Shown below is the results for the 10x instrument.

Right exit pupil.

Left exit pupil.

Both pupils are perfectly round, so no truncation here. There is some light outside the exit pupil but this had very little effect in practice, as my subsequent tests showed.

Placing an intensely bright light at a distance of about 5 metres and examining the focused images through both instruments produced pretty much identical outcomes. Both showed very good results, with only a few minor (read very low intensity) internal reflections, no diffraction spikes(as expected with Porro models) and no diffused light around the beam, all indicative of high quality, homogeneous glass. Testing on a bright sodium street lamp after dark showed excellent results too – again clean with no annoying internal reflections. So far, so very good!

In agreement with all of the reviewers cited in Preamble 2, 3 and 4  above, the daytime images delivered by these binoculars are very impressive. Both deliver very bright, high-contrast images, with very large sweet spots. Even the edges near the field stop are satisfyingly sharp. Colours are very faithfully represented and appear neutral to my eye. Chromatic aberration is very well controlled. It’s pretty much non existent for the most part but a trace can be seen when viewing roosting corbies perched high on treetops against a grey sky background. A small but very tolerable amount of lateral (off axis) colour can also be witnessed when viewing branches near sunset against an overcast sky. Incidentally, the light transmission of these instruments was measured by allbinos to be in the region of 88 per cent, so these are very efficient light cups which will prove especially useful for my primary use for them – astronomical viewing.

Glare suppression is excellent too. Indeed, when comparing the images in both my Japanese-made SR.GA 8 x 32 and the Imagic TGA 7 x 50, I judged the latter superior in this regard. On dull afternoons, for example, glare usually manifests itself in most binoculars when glassing in the open air, in the direction of the Sun. Under these conditions, the 7 x 50 produced a slightly more contrasted view when imaging a hill top. Veiling glare was also slightly better controlled in the 7 x 50 Imagic TGA too. You can readily test for this by imaging the topmost boughs of a tree against a bright overcast sky with the Sun nearby. Indeed, consulting my notes on the smaller 8 x 32 Imagic TGA model,  I had already noticed this when I briefly compared it to my newly-acquired SR.GA.

This may come as a surprise to some readers, as the SR.GA  is arguably one of the best modern compact Porros available until recently(they replaced Opticron’s excellent HR series you’ll remember). I understand the Imagic TGA models are also Japanese-designed but are actually manufactured in China. So what’s going on here? I think it’s the coatings applied to the lenses and prisms on the Imagic TGAs. These were introduced later than the SR.GAs and so may have benefitted from slightly better coating technologies. Just a hunch, but I’ve yet to come up with a better explanation!

I took some images with my Iphone 7 hooked up to the 10 x 50 Imagic TGA, using my Nikon EII 8 x 30 as a control and comparison. Both are 10-burst images taken with a 3-second delay to reduce vibrations. They were taken just a few minutes apart on the afternoon of August 27 2022. The results are shown below:

Image through the Opticron Imagic TGA WP 10 x 50.

Image captured through the Nikon E II 8 x 30. 

  • The reader will note that the field of view of the 10 x 50 is 5.3 angular degrees (confirmed later by measurement). The Nikon E II 8 x 30 is a world-class compact Porro with a stupendously wide field of 8.8 angular degrees.

You can make up your own mind about these images.

Notes from the Field

Both these large aperture binoculars are extremely comfortable to look through, with no blackouts experienced while panning across a landscape. Close focus on the 7 x 50 was measured to be 5.6 yards while the 10 x 50 was slightly longer at 5.9 yards. Both instruments present nice, well defined field stops, as well as instantly recognisable stereopsis. This is especially noticeable when viewing  objects in close proximity to each other, such as in a forest, with the 10x glass being a little bit more pronounced in this regard. This is yet another feature I find particularly charming about Porro prism binoculars in that they readily deliver views with more spatial information owing to the larger separation of the objectives than in their roof prism counterparts. I had a particularly vivid experience of this stereoptic effect in the very early morning of August 7, when I sat, completely enchanted, observing a magnificent dragonfly hovering over my brother’s garden pond in South Wales. The mist was still dissipating from the water’s surface in the cool of the morning, as I watched in sheer amazement as its iridescent wings, bulging compound eyes and body glistening in the feeble, hazy sunshine some 10 metres in the distance. I became totally captivated by the dexterity with which it manipulated its two sets of wings, changing both their orientation and power stroke from moment to moment before accelerating at breakneck speed off into the distance. I later found out that these giants of the flying insect world have been clocked moving at more than 18 miles per hour!

“How wondrously designed these creatures are,” I thought to myself. Small wonder they’ve served as the inspiration behind drone technology and a whole raft of artificial visual systems that enrich human life.

The 7 x 50 gives an ultra-stable viewing experience owing to its lower power, allowing the user to view for significantly longer periods of time. That said, I found viewing through the 10x glass to be the more immersive of the two, despite its smaller field of view(5.3 degrees as opposed to 6.0 degrees for the 7x 50). Depth of field is noticeably deeper in the 7x instrument though. Indeed, having both instruments readily at hand, I conducted some measurements of this with the help of my son’s golf rangefinder. Carefully targeting well defined objects in the centre of the field to minimise the effects of field curvature, the 7 x 50 unit delivered a close focus at infinity of 50.9 yards, while the 10 x 50 produced a value of 70.5 yards.

In previous work, I fleshed out some of the details of the factors that influence depth of field, showing that the most important parameter was magnification and which scales inversely with power. I thus expected a (10/7)^2 or two fold greater field depth in the 7x 50. Plugging the figures in yielded (70.5/50.9)^2 = 1.92, in close agreement with theory.


Large aperture instruments such as these naturally come into their own in low light situations, such as late evening viewing. Observing at sunset, and about half an hour into the dusky twilight, I was readily able to discern that the 7 x 50 yielded brighter images of targets set in the shade, such as leaf litter under bushes. But here’s the thing; I was very impressed by how well the 10 x 50 was keeping up! Magnification is, of course, at play here, providing a more enlarged view of targets which partially compensates for the grater brightness of the lower power glass. I mean, what good is a brighter image if it doesn’t show detail? You can find more on this interesting topic here.

Ad Astra

Although I could more or less instantly tell both instruments were well collimated in daylight tests, I was easily able to verify this under the stars. Centring the bright star Altair in both the 7 x 50 and 10 x 50, I turned the dioptre setting to the end of its travel, defocusing the star from a tight pinpoint to a defocused anulus of light. Both instruments showed the focused star well inside the anulus, indicating that both instruments had their barrels well aligned.

Turning to the Big Dipper, I took the opportunity to test the size of the field of view in the 10x glass by noting that the pointer stars(which show the way to the North Star, Polaris), Dubhe and Merak are precisely 5 degrees 21′ apart, or 5.3 angular degrees. I was delighted to see that both stars could just fit inside the field of view, so no discrepancy here with the stated field size. Impressive!

While I was in this part of the sky, I took the opportunity to hunt down the two Messier galaxies in The Great bear – M81 and M82  – easily swept up by drawing an imaginary line from Phecda through Dubhe and extending that line as far again until I could see both galaxies close to each other in the same field of view. Comparing the views in the 7 x 50 and 10 x 50, it was immediately obvious that the 10x glass showed these faint fuzzies considerably better than the 7x glass. This is all textbook behaviour for these binoculars. The 10x glass delivers ~ 0.5 magnitude boost over the 7x glass. The main reason is the larger magnification of the 10 x 50, which darkens the sky approximately (10/7)^2 or 2x greater than the 7 x 50, making these faint objects stand out better in the former. This is a very convenient way to see the immediate benefits of a 10 x 50 over a 7x 50 under dark skies.

But it was also obvious when I turned the binoculars over to the Alpha Persei Association in Perseus, where the 10 x 50 swept up more stars than the 7 x 50. The same was also clear from looking at the Double Cluster, located roughly midway between Cassiopeia and Perseus. Fainter stars could be seen in the 10x glass than the 7x glass.

Bringing both the 7x 50 and the 10 x 50 to a very dark site in rural South Wales during warm and settled summer weather afforded ample opportunities to do some quality stargazing. For the steadiest, deepest views, a monopod is recommended with either of these instruments, but on this occasion, I enjoyed simply hand-holding them while lying back on a zero gravity chair. Views of the Milky Way through Cygnus were breath-taking in both binoculars, particularly in the region around Sadr. What I really like about these binoculars is their very well corrected fields. As I’ve stated before, optical defects are much easier to see under the stars than during the daytime, when the eye tends to be overwhelmed by the amount of detail seen in and around the centre of the image, but star images are less forgiving. Under some super dark skies and the Moon setting early in the first week of August, I could see that the central 80 per cent or so of the field of these binoculars produced sensibly perfect star images, but in the outer 20 per cent, the effects of field curvature began to manifest themselves. Thankfully, these aberrations were very mild(as you can see from the photos taken above), with the images nearly all the way up to the field stops still being acceptably small and sharp to my eyes. Indeed, the views very much reminded me of those served up by my largest binocular – the Pentax PCF 20 x 60 WP, with its aspherical eyepieces – only with a much wider field( 5.3 compared with just 2.2 degrees).

Images of the Moon in both binoculars displayed excellent contrast and sharpness, and I could detect very little in the way of chromatic aberration in the centre of the field, with lunar craters peppering the southern highlands with impressive clarity. Off axis, a small amount of lateral colour (mostly yellows and a splash of purple) began to creep in but that’s all par for the course in most any 10 x 50 you’ll look through.

The formidable light gathering power of these high-quality Porro prism binoculars from Opticron proved very beneficial for enjoying the colours of bright stars. I enjoyed some magnificent views of the Pleiades in the wee small hours of late August, as well as M34 in Perseus, and the ghostly light from the Great Spiral Galaxy in Andromeda(M31). The Dumbbell Nebula(M27) in Vulpecula looked terrific too in the 10 x 50 but less impactful in the lower power of the 7x glass. The same was true when I turned the instruments on the Coathanger asterism(Brocchi’s Cluster) nearby. And moving back across the sky into Cassiopeia, I compared and contrasted the view of the ET Cluster in both instruments, with the victory, once again, going to the 10 x 50.

The excellent sharpness and contrast of these binoculars proved ideal for observing colourful single, double and multiple stars, with the 10 x 50 coming out on top once again. Mu Cephei – Herschel’s Garnet Star – was compelling in deep red, as were the beautiful colour contrast binocular doubles O^1 Cygni and Delta 1 & 2 Lyrae sailing high in the late Summer sky. Colourful stellar associations, such as brilliant white Altair contrasted against the  orange giant star, Tarazed, in the same field, were admired in all their preternatural beauty.

The Vortex Diamondback HD 10 x 50 is no match for the Opticron Imagic TGA WP 10 x 50.

I’m of the opinion that star images are more aesthetically pleasing through good Porro prism binoculars, owing to their complete lack of diffraction spikes. I came to notice this in comparing a few bigger roof prism binoculars with the 10 x 50, and in particular, a Vortex Diamondback HD 10 x 50. During daylight tests, for example, the Opticron Imagic TGA WP  10 x 50 produced crisper images with noticeably better contrast and less glare than the big Vortex roof. But that really didn’t surprise me as you’d probably have to fork out at least two or even three times more money to get a roof prism model that can compete favourably with these very well appointed Porro glasses. Under the stars though, the Diamondback HD did quite well, but didn’t quite deliver the same off-axis performance to the 10 x 50 Imagic TGA WP I compared it to. Eye relief is noticeably shorter on the big Diamondback HD too(16mm). It was also a little bit heavier(~850g) than the Opticron, which counts in extended hand-held use.

Are there better Porros out there? Yes, the Nikon SE 12 x 50 comes to mind, or a Fujinon FMT 10 x 50, or even a classic Swarovski 10 x 50,  but these cost several times more than either of these binoculars – if you can even get them. But if, like me, you can live with the smaller field of view offered by these instruments, you’re in for a real treat when you test them out in daylight or better still, under dark, starry skies where they’re in their element. Couple all this to their modest cost – both under £200 – and Opticron’s excellent 30-year warranty, and you may begin to see why it’s really hard not to like them!

Highly recommended!



Neil English has been observing the night sky for over 40 years. His latest book on binoculars will hit the shelves at the end of 2023.





De Fideli.

Product Review: Olympus EXPS I 10 x 42.


The Olympus EXPS I 10 x 42 package.

A Work Commenced August 20 2022


Product: Olympus EXPS I 10 x 42

Country of Manufacture: China

Exit Pupil: 4.2mm

Field of View: 96m @1000m(5.5 angular degrees)

Eye relief: 18.4mm

Dioptre Compensation: +/- 3

Coatings: Fully Multicoated Optical System, UV Coating, High-index Bak-4 Porro Prisms

Eyepieces: Aspherical design

ED Glass: No

Waterproof: No

Close Focus: 5m advertised, 3.38m measured

Weight: 785g advertised, 790g measured

Dimensions: W/L – 13/18.7cm

IPD Range: 60-70mm

Accessories: Soft case, padded logoed neck strap, rain guard, objective lens caps, instruction sheet.

Warranty: 25 years(European)

Price(UK): £154.36


Recently, an amateur astronomer I correspond with told me how much he liked the Japanese camera giant Olympus’ entry-level model; the DPS I 8 x 40. Intrigued, I decided to buy in one of their premium Porro prism models; the EXPS I 10 x 42. Unlike the DPS I models which only have fully coated optics and BK7 prisms, the EXPS I instruments featured BAK4 Porro prisms and a full multicoating in a sleek, ergonomically advanced chassis.

A Walk Around the Instrument

The instrument arrived in a very similar blue box to the DPS I models, with the instrument neatly stored away inside a soft black carry case. The binocular also came with plastic objective lens caps and rain guard, together with a nice logoed neck strap.

Groovy as you like: the Olympus binocular comes in a big, blue box.

The instrument itself is very solidly made, with a thick rubber armouring. In the hand, the instrument felt quite hefty but its redesigned contouring made it very easy to hold in a comfortable position. I measured the weight of the instrument without its neck strap to be 790g.

The nicely contoured chassis of the Olympus EXPS I 10 x 42.

The focuser is Excellent.! I mean really, really Good!

Thick rubber-clad with really good grip. It moves with silky smoothness with no free play or backlash. It’s very fast too; taking just three quarters of a revolution anticlockwise to go from closest focus to infinity, and a little beyond.

Underside of the Olympus EXPS I 10 x 42. Note the nicely delineated dioptre settings.

The dioptre compensation ring is located under the right ocular lens and has just enough tension when rotated to hold its position well. There is a scale that allows you to easily memorise your optimal setting.

The eyecups are fully modern and twist up before locking in place, giving generous eye relief. The specifications state 18.4mm. I didn’t measure this but I could very comfortably engage with the entire field with my eyeglasses on, so no worries there.

The ocular field lenses are large and easy to engage with.

The modern, twist-up eyecups are nicely made and hold their position well.

The objective lenses have very nicely applied anti-reflection coatings and are quite deeply recessed to protect against dust, rain and extraneous light.

The central hinge is quite rigid, but I did note the rather narrow IPD range from 60 to 70mm. That pretty much rules it out for those who have smaller faces or narrow set eyes.

All in all, I would rate its ergonomics very highly indeed. But what about the optics?

Optical Assessment

As usual, I began by shining an intensely bright light from my Iphone 7 torch situated several metres away and examined the image presented by the binocular. I noted a few minor internal reflections which were certainly a bit more prominent than I’ve witnessed in other similarly priced Porros from other manufacturers. Next, I examined the exit pupils of the instrument. As you can see below, there was no sign of any truncation as evidenced by the perfectly round shafts of light, but there is a considerable amount of extraneous light around and in close proximity to the exit pupils. When I pointed the instrument at a bright yellow sodium street lamp after dark, I could detect some weak internal reflections but nothing too distracting. Close focus was considerably better than advertised; 3.38 metres compared with the 5 metres quoted in the specifications sheet.

Right exit pupil: the blue reflection is from a TV in the background.

Left exit pupil.

But it was only as I began to study the daytime images that something was quite amiss. The image was good and bright in agreement with the high transmission values measured in independent tests. The centre of the image was really sharp with good contrast but the left-hand-side of the image was badly distorted in the outer 30 per cent of the field. And anywhere near the left-hand field stop was totally blurred! The same was not true on the right-hand-side of the image though. I found this aberrational asymmetry quite disturbing, especially when the field of view is quite small to start with( 5.5 degrees).

I was able to assess the situation better when under the night sky, where aberrations are much easier to identify. Centring the bright star Vega, now nearly overhead, I was able to obtain a really good, sharp image of the star in the centre of the field. Collimation was spot on. But as I moved it toward the left-hand field stop, the star became grossly deformed with what looked like a mixture of field curvature, astigmatism and coma. Attempting to refocus the star, I was only able to clean it up partially. That astigmatism and coma just couldn’t be focused out!  So much for the aspherical lens elements advertised by Olympus!

I took the liberty of capturing a photo of the image on a flat rooftop several tens of metres away. The below image is a 10-burst image taken through my Iphone 7. I think you can easily make out the very badly distorted image near the left-hand field stop.

Image captured of a nearby flat roof. Note the bad distortion on the left-hand-side of the field.

What a disappointment!

A de-centred element in the optical train? Maybe.

In other daytime tests, I compared and contrasted the image to another, similarly priced Porro prism binocular – the Opticron Imagic TGA WP 10 x 50. Comparing the views on a variety of targets and in different lighting conditions showed the Olympus EXPS I 10x 42 to have substantially more glare and less contrast than the former. And compared with the excellent edge-to-edge sharpness of the Opticron, the Olympus EXPS I was downright shoddy.  I was also disappointed with its ability to control veiling glare, easily tested for by looking at the branches of a conifer tree with the Sun immediately above it. The Opticron image was clean and well contrasted in contradistinction to the badly washed-out Olympus EXPS I image. Now this was not exactly an apples-to-apples comparison, but it was enough to deliver my verdict; this so-called ‘premium’ binocular from the famous camera giant Olympus was nothing of the sort! This is an instrument I cannot in good conscience recommend, especially when there are other models in the same price range that deliver much better optical performance.

Comparing the image quality of the Olympus EXPS I 10x 42(left) and the Opticron Imagic TGA WP 10x 50(right).

I was intrigued by the report of the less expensive Olympus DPS I 8 x 20 provided me by my astronomer pen friend, but its specifications lend me to believe that it might even be worse than this EXPS I.

My tests are all the more disappointing in light of the great ergonomics of this Olympus binocular, but it counts for nothing if the optics are so disappointing! The reader will also note that my unit did not fare as well as the unit reviewed by linked to in the text above.

Not recommended!


Post Scriptum: August 25 2022

A second unit of the Olympus EXPS I 10x 42 was ordered up for testing but proved to have the same optical issues as the first unit.

Dr Neil English has tested binoculars of all genres to build a sizeable portfolio of work for his up-and-coming book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts, which hits the bookshelves in late 2023.

De Fideli.

Product Review: Helios Star Field 2 x 40 WA Galilean Binocular.

The Helios Star Field Wide-Angle 2 x 40 Galilean Binocular package.

A Work Commenced July 28 2022


Product: Helios Star Field 2 x 40WA

Country of Manufacture: China

Magnification: 2x

Aperture: 40mm

Coatings: Fully Broadband Multi-Coated

Eye Relief: 10mm

Close Focus: 2m advertised

Field of View: 445m@1000m(24 Angular Degrees)

Weight: 189g advertised and measured

Size: 12.2 x 4.9 x 3.8cm

Accessories: Neck strap, semi-hard zipped case, microfibre cloth, instruction sheet

UK Price: £99.00

There’s nothing new under the Sun, and then some. Opera glasses have enjoyed a long history owing to their ability to generate low power, wide-angle views, enabling the theatre goer to get an ultra-stable view of the stage. In the past few years though, the opera glass has been modified to create a new type of observing experience under the starry heaven – enter the super-wide angle constellation binocular, employing powers not much more than 2x and offering up exceptionally large fields of view up to 36 degrees or so. Several models offering this kind of experience have been launched by companies such as Vixen, Orion USA and Svbony. But recently the well-known company Helios, now owned by Optical Vision Limited, has also produced their own rendition of this binocular to sate the demand of this niche observing experience; enter the Star Field 2 x 40 WA Galilean binocular. Having owned and tested out the Svbony SV 407 2.1 x 42, I was curious to learn about the Helios model, owing to its significantly smaller size and lighter weight, which would naturally lend itself to longer hand-held views.

Before getting into the details of this model, let’s look at the optical concept behind all these devices. First off, these are not true opera glasses – the eyepieces have additional lens elements to reduce aberrations inherent to the Galilean telescope design and greatly widen their field of view. This means that there will exist models that boast the same fields of view but at higher power, mostly attributed to the design of the eyepiece. The next thing to remember is that the human eye cannot harness the full light gathering power of these binoculars. On paper the exit pupil of the Helios Star Field 2 x 40 is 20mm. The human eye pupil however has a maximum aperture of 7mm, and as we age the aperture of the exit pupil decreases somewhat. So, let’s just say we have a 6mm exit pupil(which is probably realistic for a middle-aged individual like me). Thus, the effective aperture will be 2 x 6 = 12 mm. So, effectively we’re dealing with a 12mm binocular offering a 2x magnification. So what’s the deal with the 40mm aperture of the objectives? Well, it turns out that in the Galilean optical design, the field of view it delivers is dictated by the size of the objectives – the larger their size, the greater the effective field of view. The reader will note that this principal does not apply to conventional binoculars.

The 2x magnification will darken the sky by a factor of 2^2 or 4 times, and it’s the combination of the effective 12mm aperture and the 4-fold darkening of the sky that limits the faintness of stars visible through the instrument. In practice, this results in a boost of about 1.5 magnitudes – a useful gain in sensitivity over the naked eye view.

Owing to the nature of the design of these super-low power modified Galilean binoculars, there is no well-defined field stop and since the exit pupil of these designs is virtual, that is, it’s positioned inside the optical train, there is no fixed locus to image the field of view. What this means in practice is that the closer one can get to the ocular field lenses the wider the field of view experienced. Unfortunately, eye glass wearers will not, in general, be able access the same size fields as non-eye glass wearers, so these are ideally suited to the latter group of individuals. Finally, despite their advertised field sizes, off-axis aberrations significantly curtail the size of the field that offers up well corrected stellar images. And this is where the quality of the optics gets factored in. Poorer quality instruments will manifest off-axis aberrations closer to the centre than better made brands.

Now let’s take a closer look at the Helios Star Field WA 2 x 40


The first thing I noted about the Helios Star Field is its light weight. At only 189g, it’s nearly half the weight of the Svbony SV 407 2.1 x 42. And its considerably smaller too. Take a look at the size comparison below:

The Helios Starfield WA 2 x 40 (top) is smaller and considerably lighter than the Svbony SV 407 2.1 x 42(bottom).

Another view from the eyepiece end comparing the size of the Svbony glass(top) to the smaller Helios Star Field(bottom).

The optics are fully multicoated on all lens surfaces. I was unable to detect any internal reflections when pointing the instrument at a bright artificial light source.

The optics are fully multi-coated throughout the optical train ensuring bright, high contrast images with no internal reflections.

The eyepieces must be adjusted individually by turning them clockwise or anti-clockwise. The dioptre compensation range is from -5 to +3. Turning the oculars is slow  but all the while smooth.

The nicely machined aluminium eyepieces are rough textured for easy turning.

The chassis is made from high-quality machined aluminium. And while lightweight, it has the feeling of quality when you hold it in your hands. Indeed, the Svbony model, in comparison, is just plain over-built. There’s absolutely no need for a device like this to weigh so much!

The eyepieces have 10mm of eye relief; that’s not bad considering other models only have 8.5mm or so. That said, one of the things that niggles me about all these devices is that the lenses can get smudged from eyelashes rubbing against the surface, necessitating more frequent cleaning. This is not directed at the Helios Star Field  2 x 40 per se. All the other models have the same issue.

There’s no provision to mate the Star Field to a tripod, but such a lightweight device doesn’t need one. Indeed, I think it even defeats the purpose of these devices which were surely created to enjoy hand-held.

The instrument comes complete with a quality neck strap but I elected not to use it as it is so lightweight and small enough to put in a medium sized pocket.

I love the carry case that accompanies the instrument; its sturdy hard shell will protect your investment from knocks and bumps while not in use. It zips closed to keep out dust and moisture and has a neat little carry strap attached for transport.

The carry case is small and elegant. It zips closed to protect the instrument from the elements and can fit inside a jacket pocket.

All in all, the Helios Star Field WA 2 x 40 is a very nicely engineered product that feels good in the hand; top marks for ergonomics!

Daylight Optical Testing

If I’m being honest, I was quite underwhelmed by the performance of the Svbony SV 407 2.1 x 42. It had too much off axis aberrations in both daylight and night-time tests. These observations coloured my opinion of these devices so much that I was under the impression that they were all pretty much the same. Thankfully, nothing could’ve been further from the truth! Comparing the Helios Star Field  2 x 40 and Svbony 2.1 x 42 in A/B tests confirmed that the Helios was in a completely different league to the Svbony. The Helios was slightly sharper on axis, with better contrast, and had a much larger sweet spot than the Svbony. I would estimate that the effects of field curvature were not at all intrusive in the central 50 per cent of the field of the Helios Star Field but was more like ~ 30 per cent in the case of the Svbony. These differences were striking and completely unexpected!

After adjusting the eyepieces to accommodate my eyes and setting them at infinity focus, I was immediately taken by the huge contrast boost, as well as the resolution gain over the naked eye. The image showed colours far more vividly and I was able to see much finer details on high-contrast objects like the grain of wooden fences in the middle distance. Field depth is extraordinary in the Helios Star Field 2 x 40. I estimated close focus at infinity to be about 4.5-5m! After a few minutes glassing with this instrument, the view becomes so immersive and thought-provoking you can easily forget that the view is magnified. I was especially thrilled when I brought the instrument for a stroll through my local woods, where I could view vast swathes of forest with excellent clarity and depth perception. It was like having bionic eyes! Adjusting the eyepieces, I was able to obtain tack-sharp images of Red Campion beds as close as 1.9m away, so a little better than advertised. Indeed, when they come within about 10-15 metres from you, the Helios Star Field 2 x 40 served up excellent details of Blackbirds, Chaffinches and Song Thrushes foraging in the leaflitter on the forest floor. I was even lucky enough to watch the climbing antics of a little Tree Creeper inching its way up the trunk of a majestic Scots Pine some 12 metres in the distance.

One of the most unexpected dividends this neat little instrument provided was its ability to be used profitably in a moving vehicle. I brought the Helios Star Field along with me in the car. My wife was driving, and I was sat in the front passenger seat. We arrived at a stretch of road a few miles long between Strathblane and Milngavie, where I was able to enjoy stunning views of the Campsie Hills drenched in gorgeous evening sunshine. The enhanced resolution and contrast over the naked eye view turned already stunning views into sublime vistas! The magnificent escarpment came alive with intimate details of the exposed igneous rocks near their summits, with wonderful views of careening waterfalls and the ravines they had carved out over the millennia. Stunning too were the vast swathes of bracken and heather traversing the lower slopes of these ancient hills. I was amazed just how relaxing the views were. These kinds of mobile observations are quite beyond the powers of regular binoculars. If you’re ever travelling through great mountain ranges, these super-low power, wide-angle glasses are sure to enthral you with the details you can make out – and you won’t feel in the slightest way discombobulated for doing so!

Achtung: The above activities should never be carried out by car drivers!

Another daytime activity one can engage in with this instrument is cloud watching. What’s better than a cloudless summer day? A day with sunshine and white, fluffy clouds! The Helios Star Field 2 x 40 is an excellent tool for watching clouds morph in real time as they race across the sky. The obvious gain in contrast and resolution can transform a rather ordinary looking cloud mass into a veritable labyrinth of form and structure. I enjoyed a few passing minutes in the late evening sitting back in my zero gravity chair watching clouds catch the last light of a setting Sun. And even after dark, it’s wonderful to watch clouds passing by or near a bright Moon, creating wondrous spectacles of light and colour. And though I was too late this year, I very much look forward to studying noctilucent clouds into the wee small hours next summer.

Twilight can also be a wonderful time to admire beautiful silhouettes of trees, their branches showing up much more vividly compared with the naked eye. Horizons become fascinating targets with this low power glass too, with old and abandoned farmhouses, hilltops, farm silos and even windmills making fascinating targets for study as the Sun races towards the netherworld.

As mentioned previously, the instrument showed up no annoying internal reflections when turned toward a bright artificial light source at night or on a bright full Moon, so this will be a good glass to enjoy panoramic views of cityscapes and harbour lights at night.  I can also see a use for these glasses for short-range birding in the garden. If you have a bird table or feeder near to your windows, the excellent natural, immersive views of the Helios Starfield 2 x 40 will serve as a great tool for those who want to get just a little bit closer to the action.

Night Sky Testing

My first test of the Helios Starfield 2 x 40 under the stars  in my rural Scottish backyard setting came when I compared it briefly to the Svbony model described earlier. Turning the instruments towards the main stars of Cygnus lying nearly overhead, I could immediately see a significant difference between them. Specifically, when I centred Sadr(Gamma Cygni) in the field, I noticed that Epsilon Cygni was clean and sharply focused in the Helios Star Field but conspicuously blurred in the SV 407 2.1 x 42. This confirmed what I had noticed during daylight testing. It was at this point that I put the Svbony away in its case and concentrated on the Helios. I consider the latter to be poor value for money, as it actually retails for about £20 more on Amazon compared with the Helios glass.

I was immediately struck with the sheer clarity with which I could make out the entirety of Cygnus, most of Lyra and even Vulpecula. Stars quite invisible to the naked eye popped into view while glassing with the Helios and I can confirm that a solid magnitude gain of about 1.5 magnitudes was indeed realistic. I also enjoyed the view of Delphinus with its distinctive diamond-shaped asterism, as well as exploring the glories of Aquilla sat next door to it, as it were, to the west. I could immediately see how this little super-low power glass will serve as a great tool for teaching youngsters the constellations, even from a light polluted town or city.

In yet another test, I centred the Big Dipper in the Helios Star Field 2x 40 and was delighted to see that it was quite well delineated throughout. Furthermore, several ‘new’ 6-7th magnitude stars popped into view in the bowl asterism confirming its modest increase in light grasp over the naked eye view.

The Andromeda Galaxy(M31) was easy to make out above and to the east of the Square of Pegasus but when I scanned the region of the sky in Triangulum, try as I may, I could not make out even a trace of the famous Pinwheel Galaxy( M33), but my luck was to change when I brought the Helios Starfield 2 x 40 along with me on vacation to Pembrokeshire, south Wales. Here, miles away from big towns and cities, the sky is gloriously dark and transparent, and even though the Moon was in the sky, it skirted the horizon for the most part, setting early enough for me to enjoy the night sky without its ‘light pollution.‘

Here, I was easily able to make out a faint smudge of light marking the spot of M33, but I also enjoyed many short spells, lying flat on my back on a sun recliner, in absolute awe of the view served up by this low power super-wide angle binocular. The Milky Way running through Cygnus was absolutely stunning, where I could make out shoals of stars interspersed by dark, cavernous regions completely devoid of star light. In my mind’s eye, I remembered the star gazing adventures of the young Edward Emerson Barnard (who’s life is celebrated in my historical work, Chronicling the Golden Age of Astronomy), as he lay down on the back of a wagon at night, mesmerized by the blazing heavens above his head. Looking east towards Perseus I was delighted to scoop up several bright shooting stars emanating from the radiant of the Perseid meteor shower culminating on the night of August 12. And while it was still quite low in the eastern sky at or around local midnight from this vantage, I came to appreciate just how useful this instrument will be for observing other meteor showers active throughout the astronomical year.

The ‘Wonky W’ of Cassiopeia was beautifully framed in the Helios Star Field and below it, the famous Double Cluster was very easy to pick off. An instrument like this is brilliant for highlighting the smaller, fainter or more obscure constellations like Lacerta, Sagitta and Cepheus. I was also struck by how easily I could make out the colours of fainter naked eye stars. For example, Mu Cephei- Herschel’s Garnet Star – stood out as distinctly but faintly red, whereas, using the naked eye its colour is quite beyond me.

Though there were no bright comets in the sky during my testing, I can easily see how a glass like this would be awesome for observing the tail of a bright, icy interloper from the Kuiper Belt or Oort Cloud. Here’s hoping I get a chance to put this idea to the test!

It is undoubtedly the case that an instrument such as the Helios Starfield 2x 40 works best under dark, pristine skies, but I can also see many uses for it in light polluted places, where its ability to darken the sky significantly will help urban or suburban amateurs to find their way round the sky more easily.

In summary, I really enjoyed the views through the Helios Starfield 2 x 40 and would heartily recommend it to anyone. For a very modest investment of £99.00, you’ll get a nicely engineered super-wide angle binocular that delivers excellent enhancements over the naked eye. It does exactly what it says on the tin. I can’t wait to explore the glories of Taurus and Orion later in the season with this quirky little naked eye ‘extender,’ when it will help to lift the spirits above the cold and the dark of long winter nights.

Watch this space!



Dr Neil English is currently writing his 8th title: Choosing & Using Binoculars: A Guide for Star Gazers, Birders and Nature Enthusiasts, which will hit the bookshelves in late 2023.


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A Classic Pocket Binocular: The Swift Compact MK III 8 x 20.

A classic Japanese-made Swift Compact MKIII 8 x 20 pocket glass and leather pouch.

A Blog Commenced July 26 2021


It’s no secret that I’ve got a special fascination for pocket glasses. Their charms are obvious; tiny, featherlight weight, and their willingness to travel anywhere with you. So you’ll not be surprised to learn that pocket binoculars are not just a manifestation of the 21st century; they have a long history dating back many decades.

In this blog, I want to showcase a rather intriguing model manufactured by the famous US based optics firm, Swift: enter the Japanese-made Compact MKIII 8 x 20. This afternoon I emailed Swift asking for more information about this model. They responded by saying that this model was sold in the early to mid-1980s for about $70, so about $250 in today’s money.

The instrument has a dual hinge design, allowing it to fold down into a tiny size, 9.5 cm long and 5.5cm wide. Even with its permanently attached lanyard, the instrument tips the scales at only 176g. Not that’s what I call lightweight! I only received a small leather carry pouch with the instrument. It’s textured black on the outside but has a lovely red velvety lining inside. Is it original? No idea!

The Swift Compact MKIII 8 x 20 is still in great mechanical condition despite its age.

The bridge is made from aluminium and is a little thinner than those you’ll find on contemporary models made by Leica and Swarovski, for example. The coatings on the lenses are simple, blue-tinted magnesium fluoride. I’m guessing that all the optical surfaces are fully coated but can’t be sure.

Coatings on the ocular lenses.

Coatings on the objective lenses.

The objectives are quite deeply recessed in this binocular: hopefully this will help protect it from the elements and stray light. The ocular lenses have about 10mm of eye relief; not great by modern standards but par for the course in the 1980s.

The focus wheel is located in the middle of the bridge. It’s small but easy to operate, moving smoothly and accurately. Functionally, it’s very similar to the Leica Trinovid BCA models I showcased some time back. The faux leather and smooth, black metal around the objectives work well together; very Leica-like!

The underside of the binocular showing up the good condition of the chassis. Note the faded inspection sticker on the barrel.

The dioptre adjustment ring is located under the right ocular and has a nicely graded scale. It moves smoothly but has a tendency to wander away from my ideal setting.

Details of the dioptre ring on the Swift Compact MKIII 8 x 20.

The instrument is still in good collimation, but the interior optics have developed quite a thick layer of haze which you can see in the image below of the exit pupils.

Note the prominent haze around the exit pupils.

As you might expect, a glass of this age and condition produces a dim image, with the haze causing quite a bit of extinction. Neither are the roof prisms phase coated, reducing coherent light transmission further. It’s saving grace however, is the sharpness of the image and the great field of view – a whopping 7.25 angular degrees! That’s amazing for a pocket binocular, even by today’s standards. The sweet spot is very large too. I did a star test on Arcturus around local midnight to see how well it maintained its pinpoint sharpness. The results were very encouraging: only in the outer 15 per cent or so did I detect noticeable distortion – a very good result.

I took a single shot image of the field of view through the instrument. I hope you’ll agree it’s quite well corrected!

A single shot image through my Iphone 7 showing the instrument’s sharpness and off-axis performance.


These tests persuaded me to have the instrument fully refurbished by professionals.

Insane I hear you say!

But we already live in an insane world, so this project is really small beer in the scheme of things. Besides, I would like to see just how well a high-quality 1980s pocket glass can perform compared with modern instruments.

So, I got on the phone to East Coast Binocular Repairs. After describing the size and make of the instrument and the issue with the haze in the interior, I asked if they’d take a look at it for me and they said yes. So, I packed it off to them via special delivery Royal Mail this afternoon. As soon as I hear more, I’ll report back with further details.

Fingers crossed!


To be Continued……


De Fideli.

Product Review: Opticron Aurora BGA VHD 8 x 42.

The Opticron Aurora BGA VHD 8 x 42 package.


A Work Commenced July 11 2022


Product: Opticron Aurora BGA VHD 8 x 42

Country of Manufacturer: Japan

Chassis Material: Magnesium Alloy

Exit Pupil: 5.25mm

Eye Relief: 20mm

Field of View: 141mm@1000m(8.1 angular degrees)

Coatings: S-H type multi-coating to all air/glass surfaces, Phase corrected prisms with Oasis prism coating. Hydrophobic coatings applied to outer lenses

Dioptre Compensation: +/- 5

Close Focus: 1.9m advertised, 1.94m measured

Water Proof: Yes

Nitrogen Purged: Yes

ED Glass: Yes, VHD optical system incorporating field flattening technology and high quality ED glass objective system

Tripod Mountable: Yes

Weight: 725g advertised, 711g measured

Dimensions: L/W/H 15.2×13.2×5.2cm

Accessories: Premium quality soft Cordura case with rain guard, neoprene bungee strap and rubber objective lens covers

Warranty: 30 years

Price(UK): £799.00


If you’ve been following my blogs, you’ll be aware that I’ve become quite interested in many of the optical wares offered by Opticron. With over half a century of knowledge and expertise in sports optics, Opticron has robustly established themselves as a company that brings to market excellent products at very attractive prices. Indeed, one of my most used instruments is an excellent SR.GA 8 x 32 Porro prism binocular with its very high quality Japanese optics. This instrument really pushes the envelope in terms of both optics and ergonomics in a wonderful lightweight package.

These experiences made me naturally curious about what their top-tier roof prism models could deliver, and so I took the plunge and ordered up their latest flagship model, launched in the Spring of 2021. Called the Aurora BGA VHD 8 x 42, it knocks their previous flagship model, the DBA HD+ off pole position for an asking price some £200 more than the latter.

First Impressions

The Opticron Aurora BGA VHD 8 x 42 arrived in a very attractively designed black cardboard box, with a magnetic fastener. The instrument itself was found inside a beautifully designed cordura case made in Germany. I later leaned that Swarovski package some of their world class optical wares inside cases made in the same factory. I really like the feel of corduroy, especially in hot clammy weather.  The instrument itself was packed with both its rain guard and tethered objective covers on. The package also contained a very high quality padded neoprene neck strap, a logoed microfibre cloth,  instruction manual and 30-year warranty card.

The instrument comes with a fine, German-made cordura carry case.

Holding the instrument in my hands, I was immediately taken by its very elegant, yet  somewhat understated form factor. The magnesium alloy chassis is overlaid by a tough matt black rubber substrate which is very easy to grip. Unlike the DBA HD+, Opticron decided to ditch the open bridge design in favour of a tough single-bridge connecting the two barrels.

The Opticron Aurora BGA VHD 8 x 42 has a beautifully designed and rather understated chassis.

Examining the underside of the binocular showed no thumb indents, which came as a relief to me. I rarely find good use for them, as I enjoy the freedom to find my own positions without prompting.

The underside of the instrument has no thumb indents.

The  twist up eye cups have four positions to suit most anyone’s preferred eye relief. They lock into place and hold their position well. The focus wheel is a little over a finger’s width, and moves smoothly and precisely. The dioptre setting is achieved by pulling up the top plate on the focuser and turning it to your ideal setting.

The twist up eye cups have four positions to choose from.

A high performance binocular of this calibre ought to have objectives that are well baffled and recessed deeply enough to shade them from peripheral light, dust and rain. As you can see below, the objectives are indeed recessed by as much as 10mm.

Check out the deeply recessed objectives on the Opticron Aurora BGA VHD.

The ocular field lenses are large and easy to engage with. I measured their diameter to be 24mm.


Tipping the scales at just over 700g, the Opticron Aurora BGA VHD 8 x 42 is on the light side for such a high performance instrument. The instrument feels very solid in my medium sized hands. There is plenty of room to grip it either with one hand or two. The instrument has excellent eye relief – something that Opticron seem to be especially adept at achieving. It’s a full 20mm. Keeping the eyecups down, I was able to very comfortably engage with the entire field with my varifocals on.

The hinges on the central bridge are definitely on the rigid side. But that’s a good thing. Once you’ve adjusted the binocular to accommodate one’s optimised IPD, it doesn’t budge without a reasonable degree of effort.

The dioptre adjustment is idiot proof: pop up the plastic plate on the focuser and rotate it to one’s desired setting. While it has no scale, it does not jolt out of position once the plate is pushed back down. This is a better solution than other lockable dioptre designs I’ve previously encountered, such as those seen on the Monarch HG or Vanguard Endeavor ED II, for example.

The nicely designed lockable dioptre accessed by pushing up the plate on the top of the focuser.

The centrally-positioned, milled focus wheel moves through about 1.75 anti-clockwise rotations from closest focus to infinity and a little beyond. The gearing is backlash free and near ideal, especially for birders, who often benefit from smooth, accurate but rapid re-focusing.

I’ve learned to never underestimate the value of a comfortable strap when using larger, heavier binoculars. The padded neoprene neck strap supplied with this instrument is excellent; very easy to attach, and very comfortable to wear even after many hours of glassing in the field.

All in all, the Opticron Aurora BGA VHD is a beautifully designed instrument that should meet the approval of the vast majority of individuals who use it.


Optical Assessment

My optical testing began as usual, by examining how the binocular handled a very bright light source. The results I obtained were excellent. There was no internal reflections, no diffraction spikes and no signs of diffused light around the light source. These results reveal the very high homogeneity of the glass and the excellence of the anti-reflection coatings applied. Turning the binocular on a bright sodium street lamp after dark, I got a very fine image. What was even more impressive was the off axis suppression of stray light. Bringing the sodium street lamp  just outside the field showed no ghosting of any description. I also tested this on a bright gibbous Moon in deep twilight. Putting the bright silvery orb just outside the field showed no sign of flaring or ghost images.

Next I examined the exit pupils of the binocular and the results are shown below:

Left exit pupil.

Right exit pupil.

As you can see, the large exit pupils are perfectly round with very little in the way of light leaks in their vicinity.

So far so very good!

As I put the binocular to my eyes I was amazed by the wonderful quality of the image. Indeed, it was, to all intents and purposes, sensibly perfect. The field of view is impressively large at over 8 angular degrees. Scanning the pretty flower beds on a bright sunny day in my next-door neighbour’s garden, the Aurora snapped to an ultra-sharp focus, presenting their variegated hues in beautiful natural colour. Contrast was superlative, as was the edge-to-edge sharpness of the image. The punchiness of the image was extraordinary too, no doubt attributed to the complete lack of glare in the image.

Taking the instrument out on a dull, overcast day stubbornly refused to show up any glare. Usually, looking at the ridge of a hill against a bright, cloudy sky will, more often than not, produce some veiling glare, but this top-tier instrument from Opticron refused to show anything of significance.

Chromatic aberration tests also proved exceptional in this binocular. Carefully examining a telephone pole against a dull overcast sky near sunset showed up none in the centre of the image. What was extraordinary though, is that the same instrument refused to show any lateral colour until the pole was placed right up near the field stop where the merest trace of it was unveiled. The same was true when I examined several layers of leaves on a tree against a bright overcast sky. Only at the edge of the field could I detect a trace. These results were exceptional. But to elaborate, the control of secondary spectrum in the Opticron Aurora BGA VHD was much better than both the Leica Trinovid HD and the GPO Passion HD, as my notes revealed.

Scanning the edge of a forest in bright summer sunshine showed no significant blackouts and very little in the way of a rolling ball effect. This was another genuinely surprising result, as I was expecting both these artefacts to be more pronounced, especially after test driving the Nikon Monarch HG 8 x 30 in the field, which also possessed field flatteners in an even larger field of view( 8.3 degrees). Barrel distortion was very mild in the Aurora, as evidenced by examining a stretch of fencing about 50 yards distant, moving it first to the top and then to the bottom of the field.

Collimation was shown to be just about perfect, as judged by using the dioptre adjustment to deliberately defocus the image of the bright star, Vega. I used the gibbous Moon to test for off axis blurring, chromatic aberration and to assess illumination drop off as it was moved off axis. The results were very impressive here also. The Moon remained razor sharp, with excellent contrast nearly all the way to the field stops. No unwanted colour fringing was in evidence until the orb was swung right out to the edge of the field, when a faint yellow fringe was detected. There was a modest drop off in illumination though, but no more than I’ve seen in other top-rated binoculars. Stars remained stubbornly sharp pinpoints of light across the vast majority of the field, only showing slight distortion at the field stop. This will make a first-rate astronomy binocular, as my extended night tests were to reveal.

The Big Easy

The Opticron Aurora BGA VHD 8 x 42(left) and the Nikon E II 8 x 30(right).

Close focus in the Aurora BGA VHD was measured to be 1.94m, in close agreement with the advertised stats and considerably better than their previous flagship model, the DBA HD+, with its 2.5m close focus. The majority of my targets from about 30 yards right out to over 500 yards were sharply focused simply by rotating the focus wheel a mere quarter of a revolution or so. The instrument is supremely easy on the eye – I call it the Big Easy – very comfortable, immersive and highly engaging. Indeed, I gave it to a number of my family members to test out and everyone agreed that it was a joy to hold and look through. Then I broke out my two main field instruments – the Nikon EII 8 x 30 and the Opticron SR.GA 8 x 32 to compare and contrast the views with the Aurora. The latter are two very high class Porro prism binoculars with smaller objectives than on the Aurora, so not exactly a fair test. Nevertheless, inviting my family to compare the images over a period of about 15 minutes, everyone agreed that the Aurora was superior to the SR.GA 8 x 32 in bright sunny conditions. The biggest difference here was glare, which was present to a minor extent in the SR.GA but conspicuously absent from the Aurora. Edge of field performance was also noticeably better in the Aurora too.

In other tests, we compared and contrasted the Aurora with the Nikon E II 8 x 30 but here the results were much more difficult to differentiate; both instruments produced sublime images free of any residual glare. Apart from the noticeably larger field of view and more pronounced 3D enhancement in the Nikon E II  8 x 30, we all noted their very similar sharpness and contrast. Even colour tone was very similar in both instruments, with a slightly cooler tone residing with the Nikon.

Conducting similar tests at dusk, it was very obvious which instrument pulled noticeably ahead though. The greater light gathering power and larger exit pupil of the Aurora made viewing in low light far more engaging than in the Nikon EII, which was desperately running out of light under the same conditions. As a low light binocular, the Opticron Aurora easily won the show.

These results were quite remarkable in my opinion, especially during bright, daylight conditions, as I was led to believe that no roof prism binocular under £1000 could realistically compare to the top-rated Nikon E II. That the Aurora BGA VHD could keep up favourably with the universally lauded Nikon is a testament to the quality of the optics, even though it retails for only about £200 more than the latter.

I encountered just one niggle while using the Aurora in the field. The eyecups could be a little bit tauter. They rather reminded me of the reports made by users of the first models of the Zeiss Victory SF to hit the market, and especially when comparing them to those found on the GPO Passion HD I test drove, as well as the excellent eyecups(removable) found on the Leica Trinovid HD I enjoyed using a while back. But that’s asking for absolute perfection.

Conclusions & Recommendations

The Big Easy.

It was a real pleasure testing out Opticron’s flagship roof prism model, the Aurora BGA VHD 8 x 42, which proved itself to be an excellent performer, both optically and ergonomically. I feel it is arguably one of the best buys a prospective buyer can secure for under £1000 in today’s market. This, together with the company’s excellent 30 year warranty, makes it a viable alternative to other high-end models like the Nikon Monarch HG, the Leica Trinovid HD and the GPO Passion HD, and is sure to reward the user with excellent performance in any viewing conditions.

Very highly favoured!


Neil English is currently writing an in-depth buyer’s guide for binocular enthusiasts. Choosing & Using Binoculars – a Guide for Stargazers, Birders and Outdoor Enthusiasts, will be published by Springer Nature in late 2023.



De Fideli.