A work begun December 18 2020
Instrument: Leica Trinovid BCA 10 x 25
Country of Origin: Portugal
Eye Relief: 15 mm
Exit Pupil: 2.5mm
Field of View: 90mm @ 1000m/ 5.2 angular degrees
Close Focus: 4.5m
ED glass: No
Weather proofing: Splash proof
Nitrogen Purging: Yes
Operating Temperature Range: -25C to +55C
Dioptre Compensation Range: +/- 3.5 dioptres
Coatings: Fully multicoated, P40 phase coating, HDC coatings, HighLux System((HLS), water and dirt-repellent coatings applied to outer lenses
Warranty: 10 years
Dimensions W/H/D: 6/11/3.6cm
Supplied Accessories: Neck strap, field bag, test certificate, warranty card, multi-language instruction manual
Retail Price: £370-400 UK, $499-525 USD
If you know anything about my recent adventures into the world of binoculars, you’ll already be aware that I have a particular fondness for pocket-sized instruments. I just think the idea of being able to carry one anywhere and deploy a small pocket-sized glass at a moment’s notice is an irresistible prospect. Having tested and enjoyed a variety of models in the 8x category over the last two years or so, I settled on something larger and more versatile – a Leica Trinovid HD 8 x 32 – as my general purpose instrument. But I also hankered after a smaller instrument of comparable quality to the 8 x 32, but in a 10x format, and that led me to investigate a number of models in the 10 x 25 class. Fine optical and mechanical quality were important to me, having learned that both are necessary if one intends to use it for long periods of time, and over many years. Those considerations led me to explore a few options, but in the end I decided to go with what I already knew about Leica – that they manufacture excellent, high-performance binoculars which not only deliver optically but also ergonomically, and have exceptional durability. Many users of these instruments have reported decades of flawless operation in the field.
This was especially the case since I have previously enjoyed Leica’s tiniest glass – a Trinovid BCA 8 x 20 – for the best part of a year, but its very small size rendered it quite awkward to use, not to mention it throwing up a substantial amount of veiling glare, which also got on my nerves. Its bigger brother though – the Leica Trinovid BCA 10 x 25- should be easier to hold in my hands, I reasoned, without adding much more weight, and so I pulled the trigger and purchased it from a reputable dealer – the Birder’s Store, Worcester, England – who had one of the 10 x 25s in stock. I paid £369.00 for the binocular, which included free, expedited, next-day delivery of the instrument to my home here in Scotland. Shown above is what I received in the package.
Would I be happy with my purchase? Thankfully, the answer is Yes!
Fit & Finish
The first thing I noticed about this little Leica is just how light weight it is; at just 255g it comes in at just 20g heavier than its smaller 8 x 20 counterpart! That’s quite amazing when you consider the mass of the Zeiss Terra 10 x 25 (310g), the Zeiss Victory pocket( 290g) and the even heavier Swarovski CL pocket, which tips the scales at 350g. This means that it will never be an issue carrying this instrument on even the most exhausting of excursions, including hill walking and mountain climbing – where weight is always a very serious consideration. Indeed, such weighty matters can sometimes be a deal breaker, as this reviewer concluded.
Weight considered, the other good news about this instrument is that it unfolds to become an instrument that fits my hands much better than the ‘uber-klein’ 8 x 20. Its narrow bridge and long, slender barrels mean that you can get a much better grip of the instrument; and that translates into much less anxiety while handling, and much greater viewing comfort – an important consideration for a 10x glass.
Small details count for a lot when you purchase a luxury item like this little Trinovid binocular. As a case in point, consider the neck strap that accompanies the instrument. Composed of neoprene, you simply slide it through the eyes on the side of the binocular barrels and then clip it into place. This also enables the user to disconnect the strap if need be.
One of the great joys of using these little Trinovids is their wonderful ergonomics. The pull-up eyecups are rigidly held in place and will not retract unless a sizeable down-ward acting force is exerted on them. I love the simplicity these offer, with only two options – leave down if you wish to use glasses and pull-up if you don’t. I actually prefer these eyecups to those on my larger 8 x 32 Trinovid, which offers up to six different positions in comparison.
The focusing knob on the 10 x 25 BCA is centrally placed and though on the small side, is exceedingly smooth to operate. You can feel the friction it generates while it’s being rotated, rather like moving over gritty sandpaper. An unusual feature of these pocket-sized Trinovids pertains to their dioptre setting, which unlike the vast majority of other binoculars, is housed on the right objective barrel. It works brilliantly though, just like the smaller 8 x 20, and stays rigidly in place even after many hours of use in the field.
Leica is famous for its meticulous anti-reflection coatings which are applied to all of the lenses and prisms. Looking straight through the instrument from the objective end, you’ll have a hard time seeing any reflections, almost as if the lenses have disappeared. From the side, they reflect a very subdued purplish hue. No doubt these are some of the best optical coatings available in the entire industry.
Like the smaller 8 x 20 incarnation, the 10 x 25 BCA has objectives that are not as deeply recessed (which I’ve estimated at about 2.5mm) as full size binoculars, which doesn’t bode well for suppressing veiling glare. Yet despite this concern, I was relieved to discover that these did not have quite the same problems as the 8 x 20 glass in this regard, as I shall elaborate on more fully later in the review.
The carrying pouch that comes with the Leica Trinovid BCA 10 x 25 is identical to that which was supplied with the smaller 8 x 20 unit. I reported that this pouch was just too big for the 8 x 20 and that led me to seek out a better fitting case for this pocket binocular, when I eventually stumbled on a small clamshell case which could be zipped closed.
While the supplied carrying pouch fits the 10 x 25 that little bit better, it still cannot be sealed off, so I investigated whether the clamshell would fit the 10 x 25. As you can see for yourself below, the answer is affirmative. This will prove to be the ideal storing vessel for this binocular, as it can be zipped closed and still fit inside an ordinary trouser or jacket pocket.
My first test always involves examining how well the binocular handles a beam of intensely bright light, which can show up problems with internal reflections, diffused light owing to departures from homogeneity in the glass used etc. So out came my iphone torch set to its brightest setting. The results were very good but not quite as good as I had found in the smaller 8 x 20! The image was clean, with very little diffused light, a very subdued diffraction spike, but there was some moderate internal reflections of about the same quality as I had experienced with the Zeiss Terra 8 x 25. Don’t get me wrong, the Zeiss rated very highly in these tests but it was not quite as good as my notes showed the 8 x 20 to be.
Examining a bright sodium lamp showed that all was well though; very weak internal reflections and a clean image with little or no diffused light. Examining a bright waxing gibbous Moon showed a crisp, clean image, with plenty of lunar surface detail and no visible reflections around the bright orb. Collectively, these tests showed that the various coatings and glass quality in the 10 x 25 BCA is of a very high standard.
As I’ve described in previous blogs I have absolutely no problem accommodating a small, 2.5mm exit pupil such as is found on this 10 x 25 binocular. Indeed I strongly believe that the images are especially fine when using such a small exit pupil. This is because the most optically perfect part of the eye lens occurs near its centre and Leica knows this. During bright daylight use, the eye pupil shrinks to about this size making larger exit pupils unnecessary. Sure, there are trade offs in regard to eye placement but once you get used to it, it doesn’t present as a problem. The collimation on this binocular is so precise that you will not develop eye strain even after using the instrument for many hours.
From the first time I put this binocular to my eyes, I was very impressed with the quality of the image. Targets remain wonderfully sharp across the entire field and contrast is excellent, though not quite at the same level as my larger 8 x 32. I was delighted to discover that the amount of veiling glare was not as hindering as it was on the smaller 8 x 20 model, as evidenced by glassing a column of trees under a bright, overcast sky. Even in the most demanding light conditions, the veiling glare is usually weak enough to remove simply by shading the objectives with an outstretched hand.
Colours really pop in this little binocular, with green and brown hues being particularly vivid. There is some pincushion distortion at the edge of the field but to my great surprise, chromatic aberration is nearly impossible to detect! Indeed, the level of secondary spectrum is actually less on this binocular than it is on my larger, 8 x 32 Trinovid! This is all the more remarkable since the Trinovid BCA 10x 25 does not have ED lens elements, while the 8 x 32 model does!
What’s going on here? Can an achromat outdo an ED instrument in the colour correction department? No, if all else is equal. This pleasant fiction is probably attributed to both the lower light gathering power of the 10 x 25 over the 8 x 32 format and the greater need to get one’s eye perfectly square on with the small exit pupils on the former. With the larger exit pupil of the 8 x 32, you have more wiggle room and any misplacement results in seeing some chromatic aberration in difficult lighting conditions. The small instrument gathers less light under normal conditions than an 8 x 32 of comparable quality, so I think the results I have found also reflects the relative insensitivity of my average eyes to detect secondary spectrum under standard testing conditions.
Moving from 8x to 10x in a pocket glass has been a very pleasant and rewarding experience. On paper, one might assume that a small field of view of 90m@1000m would render a tunnel vision effect, but I must admit to not experiencing anything like that. Indeed, comparing my Opticron Aspheric LE 8 x 25 with its slightly larger field of 91m @1000m, this tunnel vision is significantly more pronounced than it is in the 10 x 25 BCA. The higher magnification of the latter appears to do away with this effect. And the enlargement in detail is very impressive. Bird targets that are a strain to see in my 8x glass are much more easily picked off at 10x, though of course, the trade off here is smaller field of view.
Nor have I experienced much in the way of decreased stability of the image, oft reported by users of 10x systems over 8x. Because I can hold the 10 x 25 BCA very securely with my hands, I can get nice, stable views with little shake. That said, it does take some practice to minimise this effect, but that’s been a fun experience for me.
The Leica Trinovid BCA 10 x 25 has given me all of the joy the smaller 8 x 20 glass I had and more besides. Because it is so light, I can bring it along with my 8 x 32 to use on the spur of the moment to get a magnification boost if and when required. I use it routinely each day at home, watching the riot of activity at my bird feeders. I have fallen in love with the adorable platoons of long tailed tits that frequent the feeders in these dying days of 2020 – the way they ruffle their feathers in the Rowan tree, before swooping down to gorge on the nuts, seeds and fat balls set out for them; the way they habitually mingle with groups of blue tits before flying off somewhere else.
The close focus of the Leica Trinovid BCA 10 x 25 is about 4.5 metres, so is not great for looking at insects, rocks and flowers at close range. I knew this going forward though and was quite deliberate on my part, as I did not want the little pocket glass to compete with my 8 x 32 Trinovid which has an exceptional close focusing distance of about 0.95m. Thus, in this capacity, these instruments complement each other more than anything else.
Because a 10x glass is ideal for studying open fields, valleys and rivers from an elevated vantage, I also plan, God willing, to bring the glass along with me on hill walking excursions and mountain climbing in the coming year.
I have also discovered that the 10 x 25 is a much better tool to study the heavenly creation than the smaller 8 x 20. The larger aperture and greater magnification boost afforded by the former has allowed me to enjoy the splendours of the silvery Moon in its phases, from slender crescent to fullness, with more resolving power than the 8 x 20 could ever achieve. Stars are tiny pinpoints of perfectly focused light. Views of the more spectacular deep sky objects, such as the Sword Handle in Orion, the Alpha Perseii Association, the Beehive and Double Clusters and the comely Pleaides and magnificent Hyades, are very satisfying. Indeed, comparing it to my 8 x 25, I especially enjoy the wonderful aesthetic effect of its imparting a darker sky background in the 10 x 25. So, while not being able to pull in as much starlight as its larger sibling(my 8x 32), the view of bright stars against a sable winter sky never fails to pack a powerful punch on my retinal masses.
At the end of a very challenging year, it gives me great joy to use this tiny but optically perfect glass. And while I certainly don’t hold out much for 2021, I look forward with great anticipation to the lengthening of the days once more, so that I can more fully enjoy this beautifully crafted pocket glass.
Surely that’s not too much to ask for, is it?
Dr Neil English was a regular contributor to Astronomy Now, Britain’s best-selling astro magazine for 25 years, but grew weary of the one-sidedness of the editorial’s stance on life in the Universe and their unwillingness to entertain any other ideas which threatened their increasingly unassailable scientific views. He now writes feature articles for Salvo Magazine, whose editorial team has welcomed his content with open arms.
Thank you all for reading, and have a blessed Christmas!
Post Scriptum: On the early evening of December 23, our family finally got to see the “Christmas Star,” the great conjunction of Jupiter and Saturn. Alas we were unable to observe them at their closest on December 21 and 22nd owing to cloud cover. We took a short car trip to the top of the Crow Road to see the apparition low in the southwest sky after sunset at 16:45 UT. We brought along both the 8 x 32 and 10 x 25 to observe them quite close together. Below is a quick sketch I made with the 10 x 25.