Leica Trinovid 10x50 BA dimmer than a Swarovski EL 8x32 SV? (1 Viewer)

[BKoh]

Under what circumstances would a 10x50 be dimmer than a 8x32?

Background: I had the chance to buy a Leica Trinovid 10x50 BA. Optics clean, no fungus or hazing. Cosmetically excellent. I adjusted the diopter and looked. Sharp in-focus image, CA mild but visible. Then I used my Swarovski EL 8x32 SV to compare.

The EL was definitely brighter and colours looked more saturated. The comparison was in bright sunlight on a building rooftop. About 20m away was a children's playground with colourful structures, and a spotted dove was perched about 30m away.

The Leica's image was larger but obviously dimmer, and the colours appeared faded. I did not buy it.

In bright sunlight my pupils should contract to about 2mm, and both binoculars should produce equally bright images. This was not the case. It was not close. I wore both units and swapped between them several times to confirm it.

What could be the reason for the Leica being dimmer? Lower transmission? But even if the Leica transmitted only 80% and the EL transmitted 100% (impossible) the Leica would still be ahead because of its larger aperture, am I correct?

Actual transmission data I found for a 8x32 Trinovid BN was about 77%, 8x32 EL SV about 91%. The BA could be a little less than the BN, but total light gathering for the 10x50 BA should still beat the 8x32 EL SV. Data source (pages 26 and 33):

https://www.houseofoutdoor.com/wp-content/uploads/2021/07/From-Zeiss-Deltrentem-8x30-to-Zeiss-Victory-SF-8x32-Swarovski-NL-Pure-8x32-GPO-Passion-ED-8x32-and-Kowa-8x32-BDII.pdf

Or... was there something wrong with the Leica? Or does it simply have a more yellow tint, thus making it appear less bright? Unfortunately I forgot to note the serial number of the unit, I understand Leica made some mid-stream coatings upgrades for its binoculars.

Basically, I would like to know whether I should skip binoculars of the Leica's vintage (1995-2000) and look for something newer (2010 onwards), or find a better sample.

Intended usage: observing raptors in flight (10-20%) and astronomy (80-90%).

I live in a large, light-polluted city, with many green spaces and wetlands within easy cycling distance. I already have 8x32 (and also 8x42) so 10x50 or 12x50 could be useful.

My spotting scope starts at 19x with my eyepieces. From 8x binoculars the logical jump is to 12x (or 10x if 12x cannot be held stable). Because I have to carry everything in a backpack and cycle to my observing sites, I would set 56mm as maximum size (around 1.2kg).

If anyone has any suggestions or comments, please feel free to chime in. This is not a Leica-bashing thread, if the consensus is the unit I saw was a lemon, I'll audition other units. I was all set to buy the Leica until I took out my EL and saw the difference.

 

[yarrellii]

Bkoh, my understanding is that, unless you use the 10x50 in pretty low light conditions, the difference in objective size and exit pupil would be negated, hence the EL SV 8x32 (which is a very bright binocular indeed) will prevail. I did exactly the same experiment as you, but with a 7x50 that is otherwise a solid performer (Vixen Ultima porro), and the 8x32 EL SV is noticeably brighter during the day, and almost until sunset. It is only after sunset (twilight hours) when I start to see a difference using the 7x50. So, in short, you basically need to be under pretty dark conditions.

However, using a 8x32 binocular as the "big eyes" in a comparison, for example against a 8x25, I found that a cloudy day is enough to make the larger aperture win. I have a Zeiss Terra 8x25, which is no slouch, and a 8x32 Vortex Diamondback HD, which is not only cheaper, but I'd say it belongs to a "lower" category, and on a cloudy day the 8x32 Diamondback is noticeably brighter than the 8x25 Terra, by quite a margin, so probably there I'm getting to the limit of 3 mm vs 4 mm exit pupil, while in the case of your 10x50 BA or my 7x50 Ultima, it takes more than a cloudy day to make the difference between 4 mm and 6/7 mm noticeable. Until then, it's up to the binocular characteristics themselves (glass, transmission, colour/contrast profile, etc.).

Talking about the bright image of the 8x32 EL SV, after having compared it to many other binoculars, I'd say that it's designed to offer a remarkably "bright impression" that I think not only comes down to the transmission value, but also to the way it shows colours/contrast, it somehow makes the image look brighter, sometimes I get the impression that this comes at a cost in terms of contrast (I get a similar feeling regarding my 7x42 Zeiss FL). I feel that some other binoculars offer a more contrasty image that looks a little less bright but more powerful. I'm sure someone seasoned in optical design can explain this design choices better.

 

[SUPPRESSOR]

Bkoh, my understanding is that, unless you use the 10x50 in pretty low light conditions, the difference in objective size and exit pupil would be negated, hence the EL SV 8x32 (which is a very bright binocular indeed) will prevail. I did exactly the same experiment as you, but with a 7x50 that is otherwise a solid performer (Vixen Ultima porro), and the 8x32 EL SV is noticeably brighter during the day, and almost until sunset. It is only after sunset (twilight hours) when I start to see a difference using the 7x50. So, in short, you basically need to be under pretty dark conditions.

However, using a 8x32 binocular as the "big eyes" in a comparison, for example against a 8x25, I found that a cloudy day is enough to make the larger aperture win. I have a Zeiss Terra 8x25, which is no slouch, and a 8x32 Vortex Diamondback HD, which is not only cheaper, but I'd say it belongs to a "lower" category, and on a cloudy day the 8x32 Diamondback is noticeably brighter than the 8x25 Terra, by quite a margin, so probably there I'm getting to the limit of 3 mm vs 4 mm exit pupil, while in the case of your 10x50 BA or my 7x50 Ultima, it takes more than a cloudy day to make the difference between 4 mm and 6/7 mm noticeable. Until then, it's up to the binocular characteristics themselves (glass, transmission, colour/contrast profile, etc.).

Talking about the bright image of the 8x32 EL SV, after having compared it to many other binoculars, I'd say that it's designed to offer a remarkably "bright impression" that I think not only comes down to the transmission value, but also to the way it shows colours/contrast, it somehow makes the image look brighter, sometimes I get the impression that this comes at a cost in terms of contrast (I get a similar feeling regarding my 7x42 Zeiss FL). I feel that some other binoculars offer a more contrasty image that looks a little less bright but more powerful. I'm sure someone seasoned in optical design can explain this design choices better.

Nitrogen leaked out silver coating tarnished on prism !!!
Peter.

 

[henry link]

I don't see any need to look for any special defects in the Leica BA. It was just not a very high transmission binocular even in its day.

In daylight, with the eye's pupil determining the effective exit pupil, you would expect the same surface brightness in the image from a 10x50 and an 8x32 with equal light transmission because the light from every object that reaches the retina has the same density of photons per unit of retinal surface area. In this case, with a transmission difference of 91% vs 77%, each unit of retinal surface area receives more light from from the 8x32 in a ratio of 91 to 77, so it should appear brighter.

If the BA's prisms are tarnished that will be visible as a mottled brown stain when viewing the interior through the objective lenses.

 

[SUPPRESSOR]

I don't see any need to look for any special defects in the Leica BA. It was just not a very high transmission binocular even in its day.

In daylight, with the eye's pupil determining the effective exit pupil, you would expect the same surface brightness in the image from a 10x50 and an 8x32 with equal light transmission because the light from every object that reaches the retina has the same density of photons per unit of retinal surface area. In this case, with a transmission difference of 91% vs 77%, each unit of retinal surface area receives more light from from the 8x32 in a ratio of 91 to 77, so it should appear brighter.

If the BA's prisms are tarnished that will be visible as a mottled brown stain when viewing the interior through the objective lenses.

The Master has spoken..........Not a pop at you henry , a complement.

 

[dries1]

Still a fun glass to view with today IMO, if you like the format and have a chance to get a clean sample, go for it.

 

[Mark9473]

Under what circumstances would a 10x50 be dimmer than a 8x32?

Intended usage: observing raptors in flight (10-20%) and astronomy (80-90%).

The answer is easy, as has been said, in daytime the 14% light transmission difference will be visible.

Since you said 80-90% astronomy, at night and on condition that your eye pupil is at least 5 mm, the 10x50 has a 56% larger exit pupil than the 8x32 (by area) so will be 56% brighter, minus the 14% transmission difference, still gives about 40% in favour of the 10x50. Your 8x42 will be brighter but the 10x50 would still show more.

 

[yarrellii]

As a side note. I think I was in a similar position a while ago: I wanted a capable 10x for distance viewing and astronomy. After a long pilgrimage (which included several 12x and some nice 10x, amongst them the 10x50 Ultravid), I just felt I wasn't getting what I wanted. To my eyes, 10x didn't give me a great difference compared to 8x, and some 10x50 models were on the heavy side. It was then that I read Roger Vine glowing review of the Canon IS III 12x36 for astro, and after a lot of deliberation I ended up getting them. They have many many flaws, but I can say that for astro they're simply incredible, the IS makes stargazing a true pleasure, floating effortlessly among constellations and star fields. This has to be experience. No jittering whatsoever, and although 12x36 doesn't seem like much, they do go quite deep.
For daytime use, in spite of their many caveats there is a simple and ugly truth: they show more detail. So if you are after improving raptor ID of distant birds, like plummage, features, etc., it also makes a lot of sense.
Here you have Roger Vine's review:

Canon 12x36IS Binocular Review

www.scopeviews.co.uk

And my own impressions, probably not as positive as his:

Canon ISIII 12x36 First impressions: amateurs vs professionals

NOTE: This is a completely unscientific opinion and lacks any aspiration of technical knowledge: simply what my eyes see explained the best I can in simple terms. I hope to be able to help other users sharing my first impressions as well as gaining other insights and better understanding of...

www.birdforum.net

But, all in all, these 12x36 have so far been "my best 10x50" and have surpassed my expectations both for distant birds and astronomy. Maybe it's worth checking them out.

 

[BKoh]

Thanks to everyone who responded, especially Henry Link and Mark9473. Given the otherwise-pristine optics, it seems the Leica's fundamentally lower transmission was the issue, I have simply been spoiled by my EL SV!

yarrellii - thank you for the detailed responses. I will respond point by point.

8x32 vs 8x25 and 8x32 vs 7x50/10x50
===
If the user's pupils dilate to 4mm (but not beyond) in overcast conditions, 8x32 is brighter than 8x25, but 7x50/10x50 is no brighter than 8x32 (and is dimmer if the 8x32 has higher transmission, as you and I have discovered). After sunset, with the pupil dilated to 5mm or more, 7x50/10x50 becomes brighter than 8x32.

Brightness vs Contrast
===
Our eyes see contrast better if brightness is not excessive. Bright sunlight is one example of retina overload, when some people wear sunglasses. So perhaps binoculars with very high transmission are slightly less comfortable/contrasty in bright sunlight, but in other conditions they give better views than other binoculars that are dimmer.

Another explanation: many binoculars do not transmit equally in all colours. Depending on viewing conditions and subject matter, "unequal" binoculars might offer an improved image, like tweaking colour balance in Photoshop. However, if the tint is too obvious, it can affect viewing pleasure. I read somewhere else on this forum that Swarovski's SLCs were initially sold to hunters who prized identification above visual enjoyment, and that it was only after SLCs became popular with birders that their colour accuracy was tweaked.

 

[BKoh]

As a side note. I think I was in a similar position a while ago: I wanted a capable 10x for distance viewing and astronomy. After a long pilgrimage (which included several 12x and some nice 10x, amongst them the 10x50 Ultravid), I just felt I wasn't getting what I wanted. To my eyes, 10x didn't give me a great difference compared to 8x, and some 10x50 models were on the heavy side. It was then that I read Roger Vine glowing review of the Canon IS III 12x36 for astro, and after a lot of deliberation I ended up getting them. They have many many flaws, but I can say that for astro they're simply incredible, the IS makes stargazing a true pleasure, floating effortlessly among constellations and star fields. This has to be experience. No jittering whatsoever, and although 12x36 doesn't seem like much, they do go quite deep.
For daytime use, in spite of their many caveats there is a simple and ugly truth: they show more detail. So if you are after improving raptor ID of distant birds, like plummage, features, etc., it also makes a lot of sense.
Here you have Roger Vine's review:

Canon 12x36IS Binocular Review

www.scopeviews.co.uk

And my own impressions, probably not as positive as his:

Canon ISIII 12x36 First impressions: amateurs vs professionals

NOTE: This is a completely unscientific opinion and lacks any aspiration of technical knowledge: simply what my eyes see explained the best I can in simple terms. I hope to be able to help other users sharing my first impressions as well as gaining other insights and better understanding of...

www.birdforum.net

But, all in all, these 12x36 have so far been "my best 10x50" and have surpassed my expectations both for distant birds and astronomy. Maybe it's worth checking them out.

We are indeed in a similar situation - wanting something higher-powered for distant viewing and astronomy.

I have read many reviews of the various IS binoculars from Canon, Nikon, Fuji etc. I enjoyed your musings, they are both insightful and entertaining!

Several things discourage me from going Canon IS:

1. I live in the tropics, so a non-sealed unit risks getting fungus;
2. Reports of melting rubber;
3. Poor warranty relative to price paid; and
4. Merely adequate optics (except 10x42L)

One possibility is the Sig Sauer Zulu 6 16x42, which is clearly based on the same design as Kite's APC 12x42/16x42, but much cheaper at US$560 (backordered at Euro Optic) versus EUR 869 (backordered at Optics Trade). However the Sig is only splash-resistant (IPX4) whereas the Kite is waterproof (IPX7). The Sig does have a better warranty (lifetime optics, 5 years electronics) than the Kite (30 years optics, 2 years electronics).

So I am definitely tempted by the Sig, though reports of CA as well as IS issues make me wary. A cheap price quickly becomes expensive when you have to mail them back for a refund or repair/replacement.

 

[William Lewis]

I tend to be able to see a difference in daytime viewing between even 8x32's and 8x42's in favour of the 42's so it may be a bad sample. I had the latest model trinovid hd's until recently and found them to be nice and bright so if you could find a recent sample you may notice a decent difference-coatings have come on a fair bit in the last 15odd years. You may be better off having a look through some porro prism binoculars as well on your travels as they tend to have slightly better light transmission values due to less glass surfaces and the losses associated with roof prism geometry.

 

[cottonbase]

One possibility is the Sig Sauer Zulu 6 16x42, which is clearly based on the same design as Kite's APC 12x42/16x42, but much cheaper at US$560 (backordered at Euro Optic) versus EUR 869 (backordered at Optics Trade). However the Sig is only splash-resistant (IPX4) whereas the Kite is waterproof (IPX7). The Sig does have a better warranty (lifetime optics, 5 years electronics) than the Kite (30 years optics, 2 years electronics).

So I am definitely tempted by the Sig, though reports of CA as well as IS issues make me wary. A cheap price quickly becomes expensive when you have to mail them back for a refund or repair/replacement.

Not sure where you live but the Eurooptic page for the Sig states:

"Due to government regulations and/or manufacturer stipulations we are unable to export this item outside of the United States."

 

[BKoh]

Not sure where you live but the Eurooptic page for the Sig states:

"Due to government regulations and/or manufacturer stipulations we are unable to export this item outside of the United States."

Thanks. Amazon and Opticsplanet don't seem to have this issue but have higher prices. Perhaps Euro Optic just tags everything from Sig Sauer as non-exportable since it sells firearms too.

 

[Patudo]

Just a few quick thoughts - for what it's worth, I don't do astro but I have spent a good amount of time in Singapore (grew up there, used to visit family there until covid) and almost all my birding focuses on raptors, of which Singapore has much greater diversity of than here in the UK.

When looking at BA/BN era Leicas you need to remember they are a generation older than something like your 8x32 SV. I'm not sure any binocular with Schmidt-Pechan prisms with silver mirror coatings (Leica BA/BN, Zeiss Dialyt 8x30 and 10x40, Swarovski SLC mark II) will have the kind of clarity and brightness that modern binoculars with dielectric coatings do. I've compared my 10x40 P model Dialyt to modern sub-alphas and to my 8x32 FL (roughly comparable to your SV) and the latter definitely have a slight but noticeable edge in brightness as well as more accurate colour rendition (to my eyes anyway). Step back one more generation, and my 10x50 Oberkochen porro, with single-coated lenses and prisms, is no brighter than the multi-coated Dialyt despite the larger aperture.

That being said, I'm not sure that brightness is the be-all and end-all in birding (astro is different no doubt). This is especially true in the kind of intense sunlight you get in places like Singapore. My 10x40 Dialyt is the binocular I use most when visiting Singapore and I have hardly ever felt disadvantaged when using it. I like the 10x50 format a lot: I find the 5mm exit pupil easier on the eye for long observing sessions than 4mm (10x40, 8x32) and I find the extra magnification of 10x over 8x useful in finding and staying on distant birds. The 10x50 BA/BN is a big unit, but if you don't have to point your binoculars up a lot, for instance if you are up on a hill like Telok Blangah, weight/bulk isn't too bad.

I think if one has started with something like the 8x32 SV, that superb alpha image is a very demanding standard/reference point to match; someone accustomed to a binocular like that is likely to (as you did) find the BA series a step back in terms of image quality which you may find hard to accept. I used a single-coated 10x42 Japanese porro for many years; my 10x40 Dialyt was a real improvement over that, but now that my 10x42 SE has become my most used binocular (I've gone almost full circle to using a 10x42 Japanese porro again, but one that is a whole lot better!), when I go back to the Dialyt, as I did last month for a ten day holiday, that step back in image quality takes a bit of getting used to.

One thing you do need to keep in mind with the BA/BN era Leicas, or any binocular of that era really, is the actual age of the binocular - not just its technology, the number of years it has been in service. They are well made products with a very good reputation for durability, but 10, 15 or 20 years is a long time for seals to wear, etc - and in Singapore's tropical climate you really want a binocular to be properly sealed. Fortunately there is a Leica dealer in Singapore and you should be able to get it serviced via that route.

Having said all that, I get the impression from your posts that you should pass on the 10x50 BA (unless I suppose it's offered at a very attractive price - but even so you need to be happy with the image you see through it). The 10x50 format is worth trialling - but unfortunately both Swarovski and current model Leica 10x50s are not cheap. Given your primary use will be astro it might be worth investigating a Fujinon 10x50 FMT or one of the PRC made clones (APM etc). They seem to be well regarded by the astro guys, and when observing raptors at distance, individual focus eyepieces are not such a disadvantage.

 

[BKoh]

I think if one has started with something like the 8x32 SV, that superb alpha image is a very demanding standard/reference point to match; someone accustomed to a binocular like that is likely to (as you did) find the BA series a step back in terms of image quality which you may find hard to accept.
...
Having said all that, I get the impression from your posts that you should pass on the 10x50 BA (unless I suppose it's offered at a very attractive price - but even so you need to be happy with the image you see through it). The 10x50 format is worth trialling - but unfortunately both Swarovski and current model Leica 10x50s are not cheap. Given your primary use will be astro it might be worth investigating a Fujinon 10x50 FMT or one of the PRC made clones (APM etc). They seem to be well regarded by the astro guys, and when observing raptors at distance, individual focus eyepieces are not such a disadvantage.

Thanks Patudo.

Yes, I think coating advancements made the difference. The Leica was nice to handle, but the dimmer image was not satisfying. I would probably have been unhappy in the end.

Used 50/56mm Zeiss, Leica or Swarovski are still quite costly, for that money I can get a new Canon IS 10x42L from Hong Kong or Japan.

I am half-considering the Fuji or APM. APM has the MS ED 12x50 on sale right now. Reviews on Cloudynights of the APM 10x50 are generally very positive, and it is half the price of the Fuji.

But probably the first thing to buy is a tripod adapter for my EL SV 8x32.

 

[BKoh]

Here you have Roger Vine's review:

Canon 12x36IS Binocular Review

www.scopeviews.co.uk

And my own impressions, probably not as positive as his:

Canon ISIII 12x36 First impressions: amateurs vs professionals

NOTE: This is a completely unscientific opinion and lacks any aspiration of technical knowledge: simply what my eyes see explained the best I can in simple terms. I hope to be able to help other users sharing my first impressions as well as gaining other insights and better understanding of...

www.birdforum.net

But, all in all, these 12x36 have so far been "my best 10x50" and have surpassed my expectations both for distant birds and astronomy. Maybe it's worth checking them out.

As an update, I came across a lightly used Canon IS 10x42L for a reasonable price. They tested well in the day, brightness and sharpness were on par or at least close enough to my EL 8x32 FP. They are heavy and have the ergonomics of a brick, but the IS definitely improves the view. I bought them and look forward to using them.