Return of the Opticron Dioptron 8 x 32.

The newly-restored Opticron Dioptron 8 x 32 ; a joy to look at and through.

A Work Commenced April 16 2023

In a previous blog, I briefly described the ergonomic and optical performance of two classic compact Porro prism binoculars – a Carl Zeiss Jenoptem 8 x 30 and a 30-year-old Japanese-made Opticron Dioptron 8 x 32. The little Zeiss was gifted to a former student of mine, who has since become a keen birder. The Dioptron remained in my stable, but I hadn’t used it very much. However, after sampling some of the KOMZ 8 x 30s, I dusted down the Dioptron to see how it compared with these Russian glasses. The experience rather shocked me. The Dioptron was in an entirely different league optically and somewhat better ergonomically than the Russian instruments. Indeed, the experience made me realise just how good the little 1990s vintage 8 x 32 Dioptron really was.

When it first arrived, I had not really examined its interior thoroughly to see if it needed cleaning. However, after carefully looking inside, I was surprised to see that it did have a thin veil of haze and the beginnings of a fungal infestation which fell below my radar. So I decided to have it professionally serviced. I phoned Tony Kay at OptRep, who had done a great job cleaning up my Nikon E 10 x 35 WF, and asked him if he’d be willing to clean up the little Opticron Dioptron. He said yes, and gave me a very reasonable quote. So off it went to his workshop in Selsey, on the English south coast. A couple of weeks later, I got it back, all cleaned up and looking like new. The optics were de-stained, cleaned, set and collimated. The hinges of the instrument were also freed – all ready to enjoy a new lease of life.

Bill of Work.

I thoroughly recommend OptRep. The service is super quick, and the workmanship second to none. All that remained was to give it a good clean with an Armor All wipe to condition the soft rubber eye cups and the chassis leatherette.

The Dioptron view from above.

The view was terrific: very wide(8.25 degrees), bright, extremely sharp with a great big sweet spot. It was a little brighter than I remembered it prior to dispatching. The slight yellow tint was still there though; a common feature of good optical glass from this era. There was also a bit of glare when pointed towards strongly backlit scenes but I felt it was perfectly acceptable. All in all, I was thrilled with its performance after I spent the afternoon glassing birds at two of my local patches. Here, I’d like to flesh out some more details concerning its ergonomic and optical design, as well as disclosing more information about other incarnations of this instrument I’ve discovered since first acquiring it last year.

The Dioptron 8 x 32 has a great retro look.

Ergonomics:

This has got to be one of the lightest and smallest 8 x 32 Porros in existence, weighing in at 494g without the strap –  that’s 10 per cent lighter than the Nikon E II 8 x 30 and almost as light as the Swarovski CL Companion, the Opticron Traveler BGA ED 8 x 32 and Nikon Monarch HG 8 x 30 high-performance roof prism binoculars.

Underside .

The dioptre compensation ring, located under the right ocular lens has clearly delineated markings to quickly enable the user to set and remember his/her desired settings. However, it does tend to move, but that was easily remedied by affixing a very tightly fitting o ring around the bottom of the eyepiece that increases the frictional torque considerably. Since doing this, I’m delighted to say that the dioptre setting hasn’t budged a millimetre. What’s more, it’s nicely colour matched with the rest of the chassis so you’d hardly notice it’s there unless you point it out.

The fix for a wandering dioptre ring.

The eyecups give some eye relief but not a great deal. You can better access the field with glasses on by folding them down but even so, it’s difficult to engage with the entire field. That said, I had absolutely no problem seeing the entire field without glasses, even with the rubber cups extended. The central focus wheel is an entirely different design to the Japanese Nikon Es. For one thing, it’s much larger and considerably faster. Just half a turn clockwise brings you from closest focus – measured at 2.56m – all the way to infinity and a little bit beyond.

The chassis is mostly composed of high-quality machined aluminium with only a few plastic and rubber parts found on the bridge and around the objectives. Having rubber surrounding the objectives is a good move, as it won’t scuff the paintwork like it does on the metal-rimmed Nikon E objectives. And unlike my Nikon E II 8 x 30, which cannot reliably stand upright on a flat surface, the Opticron Dioptron can!

The instrument feels great in my medium-sized hands. The leatherette provides excellent grip and there is ample room for your fingers to engage with the focus wheel, either from the top or, indeed, from the bottom. It has a beautiful, high-quality feel about it. Indeed, you instantly get the feeling you’re handling a durable, high quality optical instrument.

The binocular is fully multicoated with the best coatings available at the time. The objectives have a strong blue tint in broad daylight, while the eye lenses display a purple-green bloom. Coatings have improved somewhat from the 1990s though, but the ones applied to this instrument are more than adequate for use in most lighting situations, but maybe not my first choice on dull winter days or at dawn and dusk, where newer coating technologies clearly excel over older treatments.

Optics

The Dioptron shows some internal reflections when pointed at a bright streetlight but they are fairly weak and not especially consequential. The exit pupils look good with minimal levels of peripheral light around them.

Left exit pupil.
Right exit pupil.

Optically, the view is very impressive; sharp, nice contrast, and commanding a large sweetspot. The instrument shows some mild pincushion distortion and field curvature out near the field stops as well as lateral colour. The field stops are beautifully delineated in the Dioptron, something I’ve really come to appreciate in binocular optics. This nifty little 8 x 32 Porro delivers terrific 3D impressions of the landscape, a feature that continues to endear these instruments to me. Comparing the Dioptron to the Nikon E II 8 x 30, I judged their central sharpness to be very comparable. The latter serves up a brighter image with more contrast though, and its superior coatings were better at suppressing glare. The Nikon E II has a noticeably wider field – 8.8 degrees versus 8.25 degrees – but the Dioptron is plenty wide enough for most applications. In addition, the Nikon E II has a significantly better close focus than the Dioptron(1.96m versus 2.56m).

I think I prefer the focuser on the Dioptron. It’s super smooth, gliding with all the gracefulness of the innards of a Swiss watch. Images snap to an absolute focus with no ambiguity. This renders it an excellent birding glass in good light. As the light fades in the evening, however, the superior light transmission of the Nikon glass is easy to see. Its images are significantly brighter. Again, these comparative tests are not meant to portray the Dioptron in a negative light, only to show how it’s a product of its time. Optical coatings have improved since the 1990s and the Nikon has some of the very best available.

The Opticron Dioptron 8x 32(left) and the Nikon E II 8x 30(right).

As soon as it arrived back from its restoration, I took it off for a saunter to one of my local patches. I was lucky enough to register my first sighting this season of a group of Swallows. At first, I was overjoyed to see just one, its distinctive fork tail gleaming in weak Spring sunshine, perched high in the trees near Culcreuch Pond, resting from its long sojourn from North Africa. But as I scanned the high branches of a few other trees in the vicinity, I caught sight of several others. Some of them took to flight, gliding low over the fields with breakneck speed. What a thrill!

On another occasion, I brought both the Dioptron and my small Zeiss Terrra ED 8 x 25 pocket binocular into the west end of Glasgow to visit my in-laws and to do a spot of urban birding. I’m glad I brought both along, because it gave me an opportunity to compare both. The Zeiss is a nice pocket glass to be sure, but it can never approach the huge step-up in performance of a high-class 8 x 30. Size-wise, there’s not an enormous difference between these instruments – both could pass as pocket binoculars – but from the point of view of sheer performance, the Zeiss didn’t even come close!

When the Dioptron was first marketed in the UK, it commanded a price tag of about £120 back in the early 1990s. But there’s an interesting twist to the story of this model. The gentleman I bought the Russian Tento 7 x 35 from, Phil Grimsey, informed me that he had acquired a Japanese-made 8 x 32 from a charity shop going under the name of Panorama Puma. It was probably made for the German market.

The Panoroma Puma 8 x 32. Image credit: Phil Grimsey.

The chassis was identical to the Dioptron as were the antireflection coatings applied.

The Panoroma Puma 8 x 32. Image Credit: Phil Grimsey.

This suggests the instrument was rebadged under several names and was not exclusively developed by Opticron. That said, Phil is also chuffed to bits with his own lucky acquisition.

So, was it worth the restoration fee? You betcha!

Sarcophagi.

I prepared a sarcophagus for the Dioptron; a simple plastic Tupperware container filled with silica gel desiccant, to dry out its interior and keep it dry, rendering it functionally fog proof so that it can work in all weathers.

Thanks for reading!

Neil English has included a chapter on classic binoculars in his new book, Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts, which hits the shelves in the fall of 2023.

De Fideli.

Exploring a Couple of Classic KOMZ 8 x 30s.

Komz BNU4 8x 30(1977 vintage).

A Work Commenced April 03 2023

After the rather joyful experience with the Tento BPC 7x 35, which turned out to be a real peach of a binocular, my interest in classic Russian glass was piqued, so I decided to investigate a couple of 8 x 30 Porro prism binoculars manufactured by another Russian optics house, KOMZ, which stands for Kazan Optical and Mechanical Plant, that specializes in the production of high-quality optical equipment. The company was founded in 1940 in the city of Kazan, located in the Republic of Tatarstan in Russia.

Initially, KOMZ produced military-grade optical devices such as binoculars and telescopes for the Soviet Union. Today, the company continues to produce a range of optical equipment including riflescopes, binoculars, telescopes, and spotting scopes for both civilian and military use.

KOMZ is known for its high-quality optics, which are made using advanced technology and precise manufacturing processes. The company’s products are also known for their durability and reliability, making them a popular choice among hunters, shooters, and outdoor enthusiasts.

In addition to producing its own line of optics, KOMZ also provides components and optics for other companies in the industry. The company has a strong presence in the international market and exports its products to over 30 countries around the world. Overall, KOMZ is a respected and well-established optics firm that has been producing high-quality optical equipment for over 80 years.

I bought two of the 8x 30 KOMZ binoculars, both from Oxfam stores; one model dated to 1977 BNU4(USSR) and the other a later BNU5 1992 (Russia) which had a 8 x30 M designation. They cost £30 and £50, respectively.

Both instruments have an all-metal quality construction, weighing about 600g. The 1977 instrument came with the groovy orange eyepiece filters, shown below:

Check out those groovy orange filters on the classic KOMZ BNU4 1977 model.

Why, one may ask, did KOMZ manufacture these filters? Well, it turns out that older Russian binoculars often came with orange eyepiece filters because they were designed for use in low-light conditions such as at dawn or dusk, where the spectral peak of the ambient light shifted to shorter, bluer wavelengths, or on cloudy days. The orange filters also helped to improve image clarity and contrast by blocking out blue light, which can cause glare and reduce visibility in low-light situations. In addition, the orange filters also provided some protection against harmful UV radiation from the sun, especially when exposed to blinding winter snow. This was particularly important for people who used binoculars for extended periods, such as hunters, birdwatchers, and military personnel.

Although both instruments are separated by 15 years according to the serial numbers, their design features look pretty much identical to my eye. The large central focus wheel on the 1977 model worked well but had a significant amount of play. The later 1992 model had a better focuser, with less free play, though I did note that a small amount remained. Testing these in some sub zero night time temperature exposures showed that they continued to work well even after exposing them for a couple of hours. Like the Tento BPC 7 x 35 I tested, these KOMZ focus wheels worked just fine in the cold.

The eyepieces are made from some kind of hard plastic and are decently comfortable but do not have enough eye relief to accommodate eye glass wearers. The right eye dioptre worked well in both instruments and I was impressed by how rigidly they kept their positions compared with several more recent Chinese and Japanese-made 8 x 30 Porro prism models I have personally tested, which did get rather sluggish when subjected to the same low temperature regimes

Both models had accumulated quite a bit of dust and grime on the outside of the chassis, but after cleaning them carefully, I was able to see that the insides had not accumulated much in the way of haze and both were fungus free. Both instruments appear to have decent quality BaK4 Porro prisms. Examining the exit pupils of these instruments revealed pretty consistent results. Below is a shot of a typical result I got by looking at the pupils placed behind a soft living room lamp.

Typical exit pupil appearance in the KOMZ 8 x 30s.

The antireflection coatings applied to the 1997 and 1992 models looked different in daylight though. The 1977 model had a pronounced purple bloom on both the objective and ocular lenses, but those on the 1992 unit were far more subdued, as the photos below reveal.

The prominent purple bloom on the 1977 vintage BNU4 model.

 

The noticeably different cast on the 1992 BNU5 8 x 30.

Testing both instruments in bright overcast conditions showed that the optics were pretty much identical in both instruments, which genuinely surprised me, as I had expected the 1992 model with the ‘M’ billing to be brighter. That’s because I understood the 1992 model to have a full multicoating.

The nicely made dioptre compensation mechanism on the right ocular.

Both served up sharp images within a nice big sweet spot very reminiscent of a mid-1980s Zeiss Jenoptem  8 x 30 I showcased a while back. Close focus was similar in both: about 3.5m. I found myself wishing that I could pull down those tall ocular cups, since I could not quite see the field stops in either instrument.

Conducting some tests after dark showed very similar results when I turned them on a bright sodium streetlamp. There was some glare and a few significant internal reflections in both instruments. The same was true when I used them in the open air, where both units showed quite dim images, and also exhibited quite high levels of glare; too much, in fact, for my liking. That’s such a pity; despite being very sharp and in possession of a well corrected and wide field of view, glare ingloriously robs the image of contrast, essentially ruining the images.

The 1977 unit enjoying some early spring sunshine.

Overall I was a little underwhelmed by these sexy looking compact 8 x 30 Russian glasses. They are nice collector’s items, and fun to play around with, but ultimately not something I would like to use on a regular basis.

Thanks for reading!

Read more about some other classic binoculars in my new book; Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts, due out in the fall of 2023.

De Fideli.

From The USSR: Test Driving a Classic Zomz BPC Tento 7 x 35 Binocular.

The Zomz  BPC Tento 7 x 35.

A Work Commenced March 13 2023

Preamble 1

Preamble 2

Preamble 3

After enjoying a variety of Japanese and German Porro prism binoculars, I began to hanker after a classic Russian glass to explore their optical quality and ergonomics. A number of names crossed my radar including Komz and Tento. That led me to do a search on fleabay for instruments that might whet my appetite and it wasn’t long before I came across an intriguing Tento-branded 7 x 35. It was going for an unbelievably low price – just £25 plus £8 shipping  – from a gentleman down in England. The unit looked to be in very good condition, with a clean interior and the seller assured me the optics were in good order. So I pulled the trigger and the instrument arrived just a few days later. Meanwhile, I did some research on Tento, which I’ll briefly discuss next.

Tento is a Russian trading company that has a long and interesting history dating back to the Soviet era. The company was established in 1968 in the city of Kazan, which is located in Tatarstan, Russia. Initially, Tento produced military optical equipment such as rangefinders, binoculars, and telescopes for the Soviet army. The company’s products were known for their high quality and reliability, and they were widely used by military personnel.

In the 1970s, Tento began producing binoculars for civilian use, and the brand quickly gained popularity among nature enthusiasts and hunters. The company’s binoculars were known for their excellent optics, robust construction, and resistance to extreme temperatures and humidity, making them ideal for use in harsh environments.

In the 1990s, following the collapse of the Soviet Union, Tento faced many challenges, including a loss of funding and a decline in demand for military equipment. However, the company continued to produce binoculars and other optical instruments, and it gradually expanded its product range to include spotting scopes, night vision devices, and other specialized optical equipment.

Today, Tento is still based in Kazan, and it continues to be a leading manufacturer of optical equipment in Russia. The company’s products are sold in Russia and in many other countries around the world, and they are highly regarded for their quality, durability, and affordability.

First Impressions

The instrument arrived well packaged inside a soft case – not the original leather one. I didn’t mind however, as if all went well, I wouldn’t be storing it inside any conventional case, as I shall explain later. The binocular apparently was originally sold with orange filters, which would have been kind of groovy, but this one didn’t unfortunately. The binocular was manufactured in 1988, so near the end of the Soviet era, based on the small circle near the serial number found on the front end of the instrument.

The Soviet era Tento 7x 35 enjoying some early Spring sunshine.

The instrument has a really solid feel and has quite a bit of heft to it – 700g in fact -but it handles very well. I’d definitely describe it as ‘Spartan.’ I was able to confirm that the optics were extremely clean with no fungus or haze inside the instrument.

The instrument appears to be multicoated as far as I could tell, but looking at the objectives in daylight revealed a possible uncoated element somewhere in the optical train. The outer objective lens element also had a pale amber coating, a common feature on many Russian binoculars from this era. The objectives are very nicely recessed – surely a good thing to protect against the elements and stray light.

The amber tinted objectives. Note the bright circle possibly indicative of an uncoated surface in the optical train.
The small circle under the serial number confirms its 1988 date of manufacture.

The rubber eyecups looked in good condition, but I immediately treated them with some Armor All to protect them better. After looking through the instrument, I found I couldn’t see the field stops so I folded them down and hey presto – I could now engage with the entire field!

The focus wheel is made from a tough plastic material, but I was really impressed with its smoothness. It’s very easy to turn and boy is it fast, taking less than one revolution to go from closest focus to infinity. The right eye dioptre compensation is achieved by turning a ring under the right ocular lens. It too moved smoothly and holds its position well.

The plastic focus wheel looks crude but it operates brilliantly.

Optical Tests

In a previous life as a telescope tester and reviewer, I spoke of my admiration for Russian optics in the form of the Tal 100R(Novosibirsk), a classic 4 inch f/10 achromatic glass which produced sharper images of the Moon and planets than a 4-inch TeleVue Genesis Fluorite F/5. I’ve also owned and enjoyed its larger sibling, the Tal 125R 5-inch F/8 refractor, so I was hoping that some of the same magic would rub off on this robustly designed binocular. I wasn’t disappointed!

The optics for the BPC Tento 7 x 35 were provided by Zagorsk Optical-Mechanical Plant(Zomz), based at Sergiyew Posad, about seventy miles from the centre of Moscow. It’s a classic Porro design with oversized, high-index BaK4 prisms delivering a very wide field of view(8.5 angular degrees). The exit pupils are almost perfectly round(see the slight truncation on the right of the pupil) with no stray light or false pupils appearing in either of the barrels. Eye relief is quite generous for an older glass like this. I was able to see most of the field with my eyeglasses on and the rubber eyecups turned down. Internal reflections are very well controlled – a little better, in fact, than a high-quality Nikon Action 7 x 35 I recently put through its paces. Only a few minor ones were seen when I turned the instrument on a bright streetlamp after dark.

Pretty as you like.

Optically, the Tento BPC 7x 35 delivers a delightfully sharp image in the centre, with a decent-sized sweet spot covering about 60 per cent of the field. Be sure to check out the several owner testimonies posted in Preamble 1 above. The instrument delivers a slight yellow tinge which I really like! Indeed, I think it adds quite a bit of vibrancy to the images. One reviewer claimed the image is reminiscent of a fine portrait painting and I tend to agree with that description. Glare is well controlled in the BPC Tento 7 x 35 too, including veiling glare. Off axis, the image shows moderate pincushion(positive) distortion and field curvature. I was also able to check collimation by defocusing a bright star using the right eye dioptre. All was well here too. Indeed, I doubt it ever needed recollimation in all its years of service.

I was keen to compare and contrast this Soviet era glass to an excellent Nikon Action 7 x 35(Japanese-made) dating from around about the same time(mid-1980s). Aiming at some moss-laden tree trunks in good March light some 40 yards in the distance I was able to clearly ascertain that the BPC Tento 7 x 35 had a little bit better contrast which brought out slightly more texture in the trunks than the Nikon glass. Greens and browns are especially enhanced in the Russian glass, although the old Nikon offered up a wider(9.3 degrees) and better corrected field of view. On axis, both instruments served up equally sharp images to my eye. In yet another test, I compared both instruments in a low light setting, observing the same tree trunks immediately after sunset. While the result was close, I felt the Nikon delivered a slightly brighter image, which surprised me, as this glass has just a fully coated billing while the Tento was understood to be multicoated. It just goes to show that you can’t really judge how bright an image can be based solely on what coatings a binocular is treated to. The Allbinos test of the larger Tento 10 x 50 sibling revealed a light transmission in the low 70s per cent, typical for a quality glass from this era. They also noted that its poor transmission at shorter wavelengths readily explains why it gives a warm yellow tint. Some folk will be put off by this but I find it quite endearing. What’s more, it will never be enough to misidentify a bird – even the most variegated – in actual use.

The Tento BPC 7 x 35(left) vs the Nikon Action 7 x 35(right).

Looking at both the Nikon Action and Tento BPC 7 x 35, the reader will note their very similar dimensions. As I’ve discussed in my review of the Nikon Action, its great optical performance is the result of using large, high-quality prisms as well as having a longer focal length than most other 35mm Porros on the market. Could the excellent optical performance of the Tento BPC 7 x 35 be attributed to its longer than average focal length also? Maybe so!

Notes from the Field

The Tento BPC 7 x 35 offers up a very relaxed viewing experience owing to its 7x magnification. Depth of field is also fantastic in this glass, minimising the need to re-focus on targets beyond a few tens of metres in the distance. Close focus was measured to be 4.39m. The fast focus wheel works brilliantly in this binocular, allowing the user to rapidly refocus when the need arises. This makes it especially useful to birders. As I spent more time with this classic Soviet era glass, I became acutely aware of why it performs so well after all these years. They were built for the harsh Russian environment. Taking advantage of a long and unseasonably chilly March cold snap, I tested how the focuser would behave in the late evening as the temperatures fell below zero outside. I had already extracted any water vapour inside the glass by storing it in one of my desiccant-filled Tupperware containers – a simple way to keep all of my Porros from fogging up internally.  I can report that even after a couple of hours in these conditions the tension of the focus wheel hardly changed at all.

Consolidating my Love of Porro Prism Binoculars

I’ve thoroughly enjoyed test driving this charming glass from behind the Iron Curtain. It works flawlessly and delivers really excellent images. Let’s just say it’s the best £25 I’ve ever paid for a binocular! But it has also consolidated my belief that roof prism binoculars are just not good value for money – and some of them are just highway robbery. To think you’d have to shell out several hundred pounds to get a roof prism model to deliver images of comparable quality leaves a bad taste in my mouth. No more roofs for me I’m afraid.

Finders Keepers!

I would recommend this binocular to anyone looking for a fine, robust glass that has already stood the test of time and will likely last another generation if looked after carefully. To render it fog proof, prepare a watertight Tupperware container filled with 20 x 10g sachets of activated silica gel. Make sure to rack out the focuser a little to ensure efficient diffusion of gases. Store your instrument inside this container at room temperature for about four days(revised down from 7 days). It will draw out any remaining water vapour inside the chassis, so it can’t fog up inside. And if you continue to store it in this way, it will remain so indefinitely.

The Sarcophagus.

Thanks for reading!

Dr Neil English offers a refreshingly new and revised take on the binocular market, based on first-hand field experience. Choosing & Using Binoculars: A Guide for Stargazers, Birders and Outdoor Enthusiasts, hits the shelves in the fall of 2023.

De Fideli.

An Extraordinarily Lucky Find: Nikon Action 7 x 35 Widefield 9.3 Degree.

 

A mid-1980’s Nikon Action 7 x 35 Widefield 9.3 degree field.

A Work Commenced January 25 2023

Over the last year, I’ve taken a deeper interest in Nikon Porro binoculars. In previous communications, I’ve described how much I’ve been enjoying both the 8 x 30 Nikon E II and the 10 x 35 Nikon E, the performance of which have really spoiled me. In more recent times I field tested the lower power 7 x 35 Aculon A 211 and Action EX and while both were enjoyable, I felt that their excessive field curvature at the edge of their 9.3 degree fields left a little something to be desired. I briefly considered the 7 x 35 E but its rather restricted field of view of 7.3 degrees didn’t sit right with me. To my way of thinking, a 7x glass is already compromised owing to its lower power – call it ‘pain’ if you like -and there ought to be some ‘gain’ in return, and that meant an enlarged field of view. So, in summary, I was after a 7 x 35 glass that offered better optics than either the Nikon Aculon or the Action EX, especially off axis.

I knew and read about some classic Porro prism binoculars from yesteryear that sported enormous fields, sometimes up to 11 degrees or more, but I wondered whether their edge of field performance would also let them down. So I began looking at classic Nikon Porros that offered something of a compromise and 9.3 degrees seemed to fit the bill the best. I’d lose a little magnification but gain a whole half a degree over my Nikon E II. But which model to choose?

Having never tested any of these out in real life, it was somewhat of a guessing game, but I had to start somewhere. The condition of the instrument ranked high on my list of priorities too. I wanted an instrument that was in good condition, with no large build up of internal haze on the prisms or, worse still, fungus. Did such an instrument exist? The answer, I’m delighted to say, is yes!

Doing some browsing on Fleabay, I came across a very intriguing instrument. This was a Japanese-made 7 x 35 Widefield 9.3 degree binocular in what looked like excellent working condition. It even had the original eyepiece and objective caps as well as the black bonded leather case – Japanese made also. And it was going for £85 inclusive of free delivery! The seller had the presence of mind to include some photos taken through the objective lenses against a plain white background, which allowed me to assess the condition of the interior lenses and prisms. It looked amazingly good for the age, which the seller informed me dated to the mid-1980s. So I pulled the trigger and sure enough it arrived two days later. Opening the package, I removed the case from the wrapping to find the instrument perfectly positioned inside. When I picked it up, I was quite taken aback by its rather large frame. This was a longer-barreled binocular than I expected any 35mm Porro to be. Take a look at it in comparison to my 10 x 35 Nikon E below:

The large frame of the Nikon 7 x 35 Widefield(left) is apparent compared with my Nikon E 10 x 35(right).

Upon inspection with a flashlight I confirmed that the innards of the instrument were indeed pristine. How on God’s Earth could a binocular that first saw light when I was a middle schoolboy still look so good after all these years? Well, the excellent condition of the chassis – with a couple of minor scuffs on the metal rims on the instrument’s mid-section– and the fact that it still had its original caps and no internal haze suggested to me that it must have been very lightly used. But it must also have been stored in a good, dry place to prevent the growth of internal fungus.

The instrument is fully coated – most probably using a single layer of MgF2 on all optical surfaces. Thus I fully expected that it would not be nearly as bright as instruments treated to a full modern multicoating. More on this later.

The coatings on the objectives appear pristine after all these years.

Unlike the later E series, the focus wheel, which also appears to be made of some kind of tough plastic, is much larger and placed right between the barrels. It was a bit stiff coming right out of the cold box, which had travelled the length of the country from the seller, but after I ‘thawed’ it out, as it were, it came back to life moving smoothly in both clockwise and counter clockwise directions, with no free play or backlash.

The Nikon 7 x 35 Widefield from above.

Splendid!

The eyepiece housings appear to be made of  some kind of tough plastic too, as were the rim of the objective barrels, which surprised me. The eyecups are made from rubber though, a significant departure from the hard plastic of the old classic Zeiss Porros. The dioptre ring is very similar to that of my Nikon 10 x 35 E, which has a tendency to wander while in field use, but I soon remedied that by fitting a very tight rubber o ring immediately under it which keeps it in place much better. The chassis is ‘armoured’ in an attractive, textured leatherette which is very nice to the touch as well as to visually inspect.

Belly side up.

Despite it being a big glass for a 35mm format, I was surprised that it tipped the scales at only 665g – much lighter than the Action EX and also lighter than the Aculon 7 x 35! The only disappointment with the instrument was a somewhat frayed neck strap, which I might have got by with, at least for a while. But having taken a short stroll with it, paranoia got the better of me, and I decided to replace it with a nice, old fashioned leather lanyard which supports its moderate weight well.

The strong blue-tinted ocular lenses. Note the leather lanyard.

The handling of this instrument is superb. I can wrap my hands round those curves in the mid-section with wonderful ease and comfort, using my middle fingers to fall naturally on the deeply ridged focus wheel. Less than half a turn clockwise brings you from closest focus (measured at 4.1 yards) to a little bit beyond infinity. All in all, this instrument, which has travelled nearly 40 trips ’round the Sun since it saw first light, is an ergonomic delight!

Bravo!

Optics

After about an hour of warming the instrument up to room temperature, I noted that all was well. The optics were clear both internally and externally. And it was at this moment that I brought it outside for a gander. Wow! This thing is super sharp! But what really impressed me was how big the sweet spot was: it was in a totally different league to the Nikon Aculon or the Action EX, which always gave me that funny goldfish bowl feeling as soon as my eyes drifted to the periphery of the field. No, this instrument was optically far superior to those other Nikon’s both on axis and especially off axis. Pure, indulgent pleasure! To access the entire field, I had to turn down the rubber eye cups in order to get a good view of the field stops, just like I had done with my Nikon E 10 x 35. Glare was surprisingly well suppressed for a singly coated optic like this; far better, for example, than my multi-coated Zeiss Jenoptem from the same era. It has a slight yellowish colour cast, very much like that achieved by a very mild photographic warm-up filter.

Both longitudinal and lateral colour correction are very well controlled. Hardly any was seen even on the most difficult high-contrast targets. Barrell distortion is mild. My first stroll with the binocular was during dull, overcast conditions. I brought it to one of my local patches, where a fallen tree occupies the far end of a pond. I’ve come to use this to judge how big the sweet spot is in many binoculars I test because it crosses the entire field. I could immediately see that its optical behaviour was much more like that of my Nikon E II 8 x 30 than either the Aculon or Action EX models. Far superior off axis performance, with the sharpness being maintained nearly right to the edge. Vertical correction was not as good though, but that’s true even with my Nikon E II 8 x 30 and virtually all others I’ve tested.

Right exit pupil of the Nikon Action 7 x 35.

My next tests took place in brilliant winter sunshine, on the formative afternoons of January 25 and 26. The views in this fabulous light were breath-taking. I could see details on the far hills that simply didn’t stand out in my tests with the Aculon and Action Ex. I quickly came to realise how little refocusing I was doing owing to the instrument’s impressive depth of field. The focus is a little stiffer than a top-rated birding binocular, but this turned out to be largely immaterial, owing to the generous field depth. I’m really coming ’round to appreciating this wonderful optical property! In bright sunlight, one hardly notices the slight yellow tint of the old Nikon Widefield 7 x 35, but as the light fades more tests conducted with my Nikon E II showed up the clear advantages of modern broadband multi-coatings. Venturing out just before sunset on a cold and cloudless late January day, I glassed some tree trunks about 80 yards in the distance. Comparing the images side by side, I could see that the Nikon E II 8 x 30 was already pulling ahead of the old classic. It had an unquestionably brighter image and better contrast between the browns of the tree bark and the green moss and lichen mottling its surface.

In yet another test, carried out in the early evening of January 26, I mounted both instruments on a tripod and studied the images of a beautiful crescent Moon sinking towards the western horizon. Apart from more internal reflections in the 7 x 35 I was genuinely impressed how comparable the images were. The Moon had a very faint fawn tint to it that I didn’t really find distracting, comparing it with the marble white colour served up by the Nikon E II 8 x 30. Colour correction was actually better on the Nikon Widefield 7 x 35 than the E II, both on and off axis. I would estimate its sweet spot is a good  75% of the field, about the same, in fact, as the 8 x 30. Illumination drop off was a bit more pronounced on the 7 x 35 though, but the effects of mild field curvature near the field stops could be easily focused out – just like the venerable E II.

Moongazing, January 26 2023.

Venturing out after midnight in the wee small hours of January 26, the Moon had set and the full glory of the winter night sky was presented to me. Cassiopeia, Perseus and Taurus were now hanging low on the north-western sky, Gemini was near the meridian and brilliant Arcturus was rising fast in the east. I enjoyed fabulous views of the Hyades and Pleiades. Framing the Auriga Messier open cluster trio in the enormous 9.3 degree field proved child’s play. I swept up the Beehive cluster in Cancer, and looking eastward I enjoyed some marvellous views of the Coma Berenices Cluster. Stars were beautiful pinpoints across most the field of view, with only slight distortion seen on the brighter stellar luminaries near the field stops. Despite its lower overall light transmission, this is a better glass than the Aculon or Action EX 7x 35s for stargazing. What it lacks in light gathering power is easily offset by its better corrected field of view.

After I had received the instrument and done some preliminary testing, I did a search to see if others had reviewed the Nikon 7 x 35 Widefield 9.3. My searches came up empty at first, as all I got was a number eBay links here and there showing some photos of the instruments for sale. Puzzled I began to read older threads on past Nikon Porro prism binoculars and eventually hit on the issue: this model was apparently known as the Nikon Action 7 x 35. What’s more, there were apparently several incarnations of the Action, with the later models being switched to production in China. What nailed it for me was finding a very interesting post on Birdforum dating to January 2012 made by Henry Link, an experienced US-based binocular enthusiast who discussed the same model. You can read his report of it here. What’s more, he came to largely the same conclusions about this binocular as I did: a Mark1 Nikon Action 7 x 35 Widefield. Furthermore, in his post he described the results of tests of this binocular, concluding that it was one of the sharpest shooters in its genre. It was, in his own words, “as good as it gets.” Link also provided a really good explanation for why the Action Mark I worked so well. It has a longer than average focal length – a full 140mm in fact – making it a slower f/4 optical system. Increasing the F ratio of any telescopic system is a way to reduce all geometric(Seidel) aberrations as well as chromatic aberration.

I contacted Henry to tell my story with a few photos of the instrument. He confirmed that it was the original Nikon Action as described.

Concluding Thoughts

What a marvellous find! To say that I’m delighted with it would be an understatement. This is a higher-class binocular than anything Nikon is currently churning out in the 7 x 35 format. But it raises as many questions as it answers. Why give up on such a great optical design? Can it be resurrected? It’s also taught me a valuable lesson; there is nothing new under the Sun and great optics can be had from pretty much any era if you’re lucky enough to stumble on them!

Neil English’s up-and-coming book, Choosing & Using Binoculars: a Guide for Stargazers, Birders and Outdoor Enthusiasts, will also include a chapter on classic instruments from the past. He would like to thank Henry Link for interesting discussions on this binocular.

 

 

 

De Fideli.

A Closer Look at Two Compact Porro Classics.

The Carl Zeiss Jenoptem 8 x 30W(left) and the Opticron Dioptron 8 x 32(right).

A Work Commenced April 24 2022

 

I don’t suppose you’ve noticed, but I’ve taken rather a shine to a number of compact porro prism binoculars of late, having spent the vast majority of my time exploring roof prism models. After having test driven a few models now, I’m rather taken by their considerable charms, not least of which is their simple design, excellent optics, and much smaller price tags than similar quality roofs. Before I pulled the trigger on a few top rated models, I took some time to get a feel for a couple of classic models in the 8x 30/32mm aperture class. Accordingly, I bought up two models on the second-hand market for field testing; the Carl Zeiss Jenoptem 8 x 30 and the Opticron Dioptron 8 x 32, as shown above. In this short blog, I’d like to relate some details about these two models and how they perform after all these years.

I purchased both models from ebay. There were many Zeiss DDR Jenoptem models available for sale in all sorts of condition. That helps stabilise their market price to between about £60 and £100 UK. I settled on a late-1980s model(serial # 6722320), with the famous T3M multi-coatings, which, for their day, were well ahead of anything else on the market.  The unit I purchased was in excellent working condition, without any visible damage to the optics, and devoid of internal fungus infestations. The binocular came in its original brown leather case, which needs a few stitches to restore it to full working order, as well as a nice leather lanyard.

The c.1988 Carl Zeiss Jena Jenoptem 8x 30 ocular lenses with famous T3M multi-coating.

The objectives looked pristine after I gave them a thorough clean:

The well preserved anti-reflection coatings on the 30mm objectives. Note the serial number indicative of the era in which it was manufactured.

Some background research informed me that the leather case originally supplied with the instrument was lined in a fetching rose-coloured lining:

The original case, with its nice rose coloured lining.

The instrument arrived well collimated. The central focus wheel operated smoothly, with no free play or backlash. I was very impressed when I took my first look through it. The image was bright and very sharp within its very generous sweet spot. I was especially taken aback by the enormous field of view; fully 8.4 angular degrees! The dioptre compensation ring, located under the right ocular, moved smoothly but was easily nudged out of place.

Observing in an open field, in bright, spring daylight, showed that glare was quite well controlled but certainly more than I’ve seen in most modern instruments. Still, the sheer majesty factor of the field of view made a very deep impression on me. I was especially taken by the wonderful 3D pop to the images, which I found very engaging. As this instrument was more than 30 years old, I was expecting some internal reflections when I turned the instrument on a bright light source; and rest assured, a few did show up.

The instrument presented a very warm image but it was not as yellow as other reports have suggested. Maybe this was because I had a quite late model of this world famous binocular – I’m not entirely sure- but I was surprised to learn that its maximum light transmission peaked at about 91 per cent in the optimal, green-yellow visual range, according to spectrophotometric measurements conducted by Allbinos on a slightly earlier, 1985 model.

Short on eye relief though, but amazing if you manage to hook your eyes up with those ocular field lenses!

All in all, a very nicely operating classic compact porro, and quite collectible even in the 21st century. It certainly puts a smile on my face every time I use it.

The next model is a later dated instrument from the UK-founded Opticron optics firm. Called the Dioptron 8 x 32, it was fashioned in Japan and dates to the mid-1990s. Thus, it represents the next step in the intelligent design of the compact porro prism binocular. I picked this model up for just £50 plus shipping.

The Japanese-made(c.1995) Opticron Dioptron 8 x 32, together with its bonded leather carry case.

Though of slightly lower profile than the Zeiss Jenoptem, the Dioptron weighs roughly the same as its German counterpart, so its one chunky little glass.

Note the nice multi-coatings on the ocular lenses.

The Japanese origin of the Dioptron is betrayed by the stamp on the front of the binocular, which unscrews to allow it to be mated to a tripod:

Made in Japan.

The instrument also arrived well collimated, which flies in the face of those who insist that porro prism designs are much more susceptible to misalignment than their roof prism counterparts. If you mistreat any binocular, you’re in for trouble. But treat them well and they will serve you for a lifetime.

The objectives show a very prominent blue anti-reflection coating, unlike the prominent purple hue on the Jenoptem objectives.

The anti-reflection coatings on the mid 1990s Opticron Dioptron 8 x 32.

The big difference between the models is the focus wheel. In a departure to classic German compact binoculars, the Dioptron focus wheel is much larger and easier to access than that of the Jenoptem. Even after all these years, it works like a dream. Very high quality indeed!

Note the much larger and easier to access focus wheel on the Opticron Dioptron.

One slightly niggly thing about both instruments is the easily moved nature of the dioptre rings. Taking them in and out of their cases generally bumps the dioptre off its optimal setting, and even when holding them up to your eyes is quite enough contact to make them wander. Thankfully, this problem is all but fixed in later models.

Overall, the Dioptron is extremely easy to use, even though it shares the same poor eye relief with the Zeiss Jenoptem. Optically, it offers up a very good image, slightly better in fact than its German counterpart, but what genuinely surprised me was the strong colour cast of the images it serves up. It was considerably yellower than the older Zeiss glass. I would describe it as very ‘warm.’ And going from 8.4 angular degrees in the Zeiss down to 8.25 degrees in the Dioptron is quite noticeable to my eye. The Opticron does have noticeably better control of glare however, which renders its images that little bit more contrasted than the Jenoptem.

Both the Carl Zeiss Jenoptem and the Opticron Dioptron classics can be enjoyed entirely on their own terms. I’ve taken both instruments out on long walks in the countryside and have thoroughly enjoyed the lovely large fields of view and very large sweet spots, as well as the characteristic 3D pop they both command. The worst of the glare is seen when these instruments are pointed near bright light sources, but a lot of this can be removed simply by shading the objectives with your hands.

Both instruments helped me to finally make the transition to using high quality porros in preference to roof prism models when using compact binoculars in the field. The transition feels entirely natural for me.

After all, I’m a dyed-in-the-wool classicist don’t you know!

Thanks for reading!

 

De Fideli.