Those Underappreciated 10x25 Binoculars (2 Viewers)

Maybe it's how I was introduced to bincoulars and birds. I don't know. But when I started eleven years ago (at a late age), it happened by way of a 10x25B Swarovski SLC that my friend Clay showed me at lunch one day. He had invested $500 in this 8 oz. bundle of precision, waterproof, P-coated optics with eight lenses in each barrel! The view was magnificent: colorful, flat and crystal clear from edge to edge.

As fate would have it a local gun dealer sold me an identical pair for only $400 (which I didn't tell Clay). Swarovski had given him these as a dealer award, but were too delicate for the rigors of hunting. Using excellent sense, he sold them to me.

These 10x25 SLCs have been with me all over the world, and have provided my first views of 90% of the birds on my life list (not that that's very large). The remaining 10% were from 8x30 Mk IIs purchased from the same dealer a year later. Historical landmarks have been observed inside and out, concerts and jazz performances — in daylight and at night. They have become my faithful visual companion.

Exposure to the combination of 10 power, quality, and extreme portability took place during my "critical period," like a duckling learning to recognize it's mother. So, everything else I come across is compared with "mother" as a reference. Many are better in one respect or another, but all fall short as a complete package. That even includes Swarovski's 8x20 SLCs, incidentally, which my wife uses exclusively.

Now I know that most manufacturers make 10x25s, and some may be as good or better than Swaro (nah, not really) ... but why has this particular optical combination been ignored by and large? Curiously, it affords a slightly better "twilight factor" (15.8) than the much acclaimed 8x30 (15.5) and is only slightly inferior to the 8x32 (16). The 8x20s compute out to 12.6 and are really not in the running for low light use ... which has been my experience. For FOV comparisons, the Swaro 10x25 compares 285' vs. 330' for the 10x42SLC. This is only a 15.7% difference to compensate for a 397% weight penalty.

Bigger binos do look more impressive I admit.

elkcub

I have two or three year old Leica 10x25 and 8x25. I like them. I thought at the time they were better than the small Swarovskies.

Why are the 25mm binouculars "unappreciated", one big reason is the small exit pupil. They are not as fast to see through unless you happen to get your eyes positioned just right behind the eyepeices. The eye relief is not as good as the better larger birding binoculars. As you mention the field of view is smaller too.

I like the 25mm binoculars, but other than being light weight, they are not as comfortable to use as the larger models.

All the best,
Rich

The better 32mm birding binoculars are twice as heavy as the better 25mm binoculars, but the 32s are quite a bit faster to look through. The 32s also have higher contrast, better images.

Rich

Rich N said:

I have two or three year old Leica 10x25 and 8x25. I like them. I thought at the time they were better than the small Swarovskies.

Why are the 25mm binouculars "unappreciated", one big reason is the small exit pupil. They are not as fast to see through unless you happen to get your eyes positioned just right behind the eyepeices. The eye relief is not as good as the better larger birding binoculars. As you mention the field of view is smaller too.

I like the 25mm binoculars, but other than being light weight, they are not as comfortable to use as the larger models.

All the best,
Rich

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Hey, Rich,
Well, that was fast. As an owner of 10x25s I'm glad to get your input about this (allbeit a different brand owner). I've always been impressed with Leica, but the ones I saw at the time were not waterproof or P-coated. The new models probably are. My Swaros have been drenched many times so I never regretted having that feature.

Personally, I've never found the small (2.5 mm) exit pupils a problem on the swaros since perfect alignment takes place when a perfect circle is seen. It's simple. I find that once I set them up, which is no more difficult than for any other binocular, it lasts all day.

I had them in the rain on a river boat in Costa Rica and confronted my first tiger herron far on the other side. The 10 power provided excellent details, and brightness comparted favorably with 8x30 BAs another tourist was using. This was at dusk. Ten minutes later we'd have needed a search light.

Like everyone says, and I agree, binoculars are a personal thing. There are lot of variables to consider, but I believe 10x25s are really more useful than they're given credit for as a total package.

Regards,
-elkcub

Does anyone know why my posts have an "Edit" button at the bottom and no one else's does? Thanks for your help.
elkcub

Rich N said:

The better 32mm birding binoculars are twice as heavy as the better 25mm binoculars, but the 32s are quite a bit faster to look through. The 32s also have higher contrast, better images.

Rich

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Not sure that I can agree with the "higher contrast, better images" statement, at least not from my experience with Swaro SLC products. It could be that modern coatings have improved contrast and image quality, but that's not necesssarily a fault of a 10x25. From what I know, Swarovski hasn't changed or "improved" the coating for the SLC 10x25, and as yet there is no EL model to compare with it.

I've heard in general that 10x40/42 binocs come into their own at distance, but at least for shore birds I personally don't see a difference in color contrast or image quality. FOV yes. I do agree that the larger bins, like the 10x42 SLC, are rock solid to hold. One would therefore need a tripod to make a valid comparison.

Don't mean to be argumentative but I'm just never wrong ... but I am highly opinionated

elkcub

elkcub said:

Does anyone know why my posts have an "Edit" button at the bottom and no one else's does? Thanks for your help.
elkcub

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So you can edit your post, but not anyone elses.

I have been using a Zeiss 8x20 when out running. After a couple of miles I reach an area of mud scrapes with waders etc and out comes the binocular for a five minute break, before running back home. I find the small exit pupil makes it hard to align the optics with my eyes, there is noticeable but not severe field curvature, flare can be a problem and the field of view is somewhat restricted. But they are a little marvel. The image is surprisingly good with no CA and good contrast and sharpness. I would never use one as a full time glass, as a larger binocular is better, but when size matters, they are first rate.

Leif said:

So you can edit your post, but not anyone elses.

I have been using a Zeiss 8x20 when out running. After a couple of miles I reach an area of mud scrapes with waders etc and out comes the binocular for a five minute break, before running back home. I find the small exit pupil makes it hard to align the optics with my eyes, there is noticeable but not severe field curvature, flare can be a problem and the field of view is somewhat restricted. But they are a little marvel. The image is surprisingly good with no CA and good contrast and sharpness. I would never use one as a full time glass, as a larger binocular is better, but when size matters, they are first rate.

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Hi Leif,

Do you see the same "Edit" at the bottom of your posts? Ah, ha, I'm relieved. How would one know unless told about it? Thanks.

As commented above, the exit pupil alighment is really not an issue with Swaro 10x25s. I see only minor field curvature (possibly due to the narrower FOV) and much less flare than my 8x30 SLCs.

Of course we are possibly talking about brand differences as well as optical combinations. Although I like my wife's 8x20 SLCs, which may be comparable to your Zeiss 8x20s, IMO they just don't have it by comparison to the 10x25s. Have you given them a peek?

elkcub

Greetings elkcub,

I wish a decent 7X25 or 8X25 were available, 7X compact binoculars seem to be non-existent, and all the compact 8X have 20mm objectives (except for the Brunton Eternas, which have too restricted a field of view for me).

For now, I'm happy with my Zeiss 8X20 compacts, I feel about the same way toward them as you do toward your 10X25's - but I still reach for my Nikon 8X32 HG's when I'm off for some serious birding - the brightness, clarity, and contrast are noticably better with the 32mm objectives. I can view longer into the evening with them as well!

Best wishes,
Bawko

Leif said:

So you can edit your post, but not anyone elses.

I have been using a Zeiss 8x20 when out running. After a couple of miles I reach an area of mud scrapes with waders etc and out comes the binocular for a five minute break, before running back home. I find the small exit pupil makes it hard to align the optics with my eyes, there is noticeable but not severe field curvature, flare can be a problem and the field of view is somewhat restricted. But they are a little marvel. The image is surprisingly good with no CA and good contrast and sharpness. I would never use one as a full time glass, as a larger binocular is better, but when size matters, they are first rate.

Click to expand...

Last year I tried the Zeiss Victory Compact 8x20 in the field and found the severe field curvature that you mention extremely annoying as well as aligning the binoculars quickly to my eyes difficult. In addition, I had "blacking out" or whatever it is called once in a while. Blacking out is something that not all users notice, but some do with certain binoculars. Maybe it's because I wear eyeglasses (trifocals) while using binoculars. I purchased Swarovski 8x20s instead. With eyeglasses for me the field of vision is small, but possibly no smaller than with the Zeiss, no alignment to eyes problems, no curvature and no blacking out. My main binoculars are EL 8.5x42 and with them no blacking out and fine field of vision. Of course there are other problems with the EL 8.5x42, especially the long focus (which has its good points for some since it permits more exact focus). Obviously, choosing binoculars is very individual and dependent on one's facial characteristics (including eye placement), whether one uses eyeglasses with the binoculars, weight, etc. That's why I sometimes am very concerned about those purchasing binoculars without trying them out first or without a firm return policy. Further, I am concerned about those who swear by reviews. Two major website reviewers in the US gave positive reviews to the Zeiss's and made no mention of the curvature. I wonder if the fact that both of us noticed it suggests that this may be a quality control problem.

Alan M.,

I am very discerning about binocular optics, and I have not noticed the curvature you are mentioning in my recently purchased Zeiss 8X20 compacts. Perhaps they have made a design change?

Best wishes,
Bawko

Atomic Chicken said:

Greetings elkcub,

I wish a decent 7X25 or 8X25 were available, 7X compact binoculars seem to be non-existent, and all the compact 8X have 20mm objectives (except for the Brunton Eternas, which have too restricted a field of view for me).

For now, I'm happy with my Zeiss 8X20 compacts, I feel about the same way toward them as you do about your 10X25's - but I still reach for my Nikon 8X32 HG's when I'm off for some serious birding - the brightness, clarity, and contrast are noticably better with the 32mm objectives. I can view longer into the evening with them as well!

Best wishes,
Bawko

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Hi Atomic,

I've been reading your other posts on the subject and imagine you're after larger exit pupils in a smaller glass. Right? 8x25s would produce a 14.1 twilight factor compared with 12.6 for an 8x20 — representing a 13% improvement. (I find the "twilight factor" corresponds with my perceptions of brightness and ability to see at low ambient levels.)

The 10x25 already has a 15.8 twilight factor, which is about the same as an 8x30, other factors aside. Given their minimal size and weight, that's why I feel they come much closer than does the 8x20 to what one would have with a larger field binoc. My point on this thread is that 10x25s seem to be lumped in with the 8x20s and not considered on their own merit.

But, don't get me wrong, the 10x25 of any manufacture is not the "best." In particular situations the 10x40/42 combination is the cat's pajamas, and in others the 7/8 x 32/42. I LOVE the Duovid 8-12 x 42. I could also use it for weight lifting exercise and it is magnificent.

Of those on the market, IMO the 10x25 configuration is the most useful of the pocket binoc configurations.

elkcub

Atomic Chicken said:

Alan M.,

I am very discerning about binocular optics, and I have not noticed the curvature you are mentioning in my recently purchased Zeiss 8X20 compacts. Perhaps they have made a design change?

Best wishes,
Bawko

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Since not everyone notices it, I think it may be a quality control problem. Or Zeiss has fixed the problem since I noticed it about ten months ago. In television servicing, the curvature would be called pin cushion distortion. The outer sides of the view had the curvature.

elkcub said:

Not sure that I can agree with the "higher contrast, better images" statement, at least not from my experience with Swaro SLC products. It could be that modern coatings have improved contrast and image quality, but that's not necesssarily a fault of a 10x25. From what I know, Swarovski hasn't changed or "improved" the coating for the SLC 10x25, and as yet there is no EL model to compare with it.

I've heard in general that 10x40/42 binocs come into their own at distance, but at least for shore birds I personally don't see a difference in color contrast or image quality. FOV yes. I do agree that the larger bins, like the 10x42 SLC, are rock solid to hold. One would therefore need a tripod to make a valid comparison.

Don't mean to be argumentative but I'm just never wrong ... but I am highly opinionated

elkcub

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Elkcub,

What year were your 10x25s made?

I use binoculars a lot. I use my Leica 10x25 at the indoor shooting range because they give good images and fit in my case easily. If I didn't wear glasses when using the Leica 10x25 it would likely be easier to line up my eyes behind the eyepiece. It is more difficult when wearing glasses. When I picked my Leica 10x25 a few years ago they were as bright as the 25mm Swarovski but I would see color fringing more easily with the little Swarovski. Maybe the color was in the process of getting exactly alinged behind the eyepiece?

My Leica 10x25 gives very nice images but the image quality through my Leica 10x32 BA is noticably better. My 10x32 has better resolution, better contrast and better color saturation.

A 10x25 is easy to carry. My maybe 8 year old Zeiss 10x25 with fold down eyecups are, I think, under 8 oz. At least they are a little lighter than my Leica 10x25. If I found my 10x25 as good as my 32mm or 42mm binoculars when it comes to the view, I would carry the 25s rather than my larger binoculars. But, I put up with more weight on my neck because the larger binoculars give me better views.

I am leaning strongly toward getting a Swarovski 8x32 EL because they give virtually the same view as the 42mm models but are lighter.

Rich

Rich N said:

Elkcub,

What year were your 10x25s made?

I use binoculars a lot. I use my Leica 10x25 at the indoor shooting range because they give good images and fit in my case easily. If I didn't wear glasses when using the Leica 10x25 it would likely be easier to line up my eyes behind the eyepiece. It is more difficult when wearing glasses. When I picked my Leica 10x25 a few years ago they were as bright as the 25mm Swarovski but I would see color fringing more easily with the little Swarovski. Maybe the color was in the process of getting exactly alinged behind the eyepiece?

My Leica 10x25 gives very nice images but the image quality through my Leica 10x32 BA is noticably better. My 10x32 has better resolution, better contrast and better color saturation.

A 10x25 is easy to carry. My maybe 8 year old Zeiss 10x25 with fold down eyecups are, I think, under 8 oz. At least they are a little lighter than my Leica 10x25. If I found my 10x25 as good as my 32mm or 42mm binoculars when it comes to the view, I would carry the 25s rather than my larger binoculars. But, I put up with more weight on my neck because the larger binoculars give me better views.

I am leaning strongly toward getting a Swarovski 8x32 EL because they give virtually the same view as the 42mm models but are lighter.

Rich

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Hi Rich,

Well, that may be an issue. I don't use glasses with binocs, and mine is the older model with rubber eyecups that I don't want to roll down. The new ones have twist out cups and could work for you. My wife's 8x20s have twist out cups, but I don't think they work well for her. She has trouble getting things lined up

The use of eyeglasses introduces a whole new dimension into binoc evaluation, — one that's hardly discussed in any depth. After all, there is a new optical lens introduced, probably made of plastic, which is corrected for the user and coated or tinted in all sorts of ways. Some are multifocal to make it more complicated. Given the added opportunities for surface reflections and prism effects, it's not at all surprising that resolution and color contrast are degraded. Frankly I doubt that it's predictable.

From my limited experience with glasses, published eye relief doesn't tell the whole story, and some binocs are much easier for me to use than others. For me the 10x42 SLC is sort of okay, but the 8x30 SLC is not. The 8x32 BN does fairly well with glasses and the Duovid 8-12x42 works even better. Someone else might see it differently though (no pun

Hey, give me some advise. I'm just now deciding between the Leica 8x32 BN and 10x32 BN. For reasons stated above, I'm inclined to buy the 10x since the twilight factor is 17.8 and that for the 8x is 16. I don't have problems lining up exit pupils and I like a larger image. The FOV is even greater than the typical 330 ft. But, ... how is the near depth of field?

Advise and opinions would be very welcome. I do want to buy a Leica though, not Nikon or Zeiss.

Thanks for a nice discussion,

elkcub

Hi Elkcub,

I just tried to measure the depth of field at the close focus of my 10x32BA. I set up two small targets sbout 4 inches apart. With the closer target at best focus, in the center of the field, the farther target was a little soft. When the farther target was in best focus, in the center of the field, the near target was in focus about half way to the edge of the field, but a little soft at the center of the field.

I really like my Leica 10x32BA. I just wish it had a little more eye relief. In the field on a bright day I notice the lack of eye relief more and it is annoying. I was so happy to find that the new Zeiss 10x42 FL has good eye relief.

Hope that helps.

Rich

Since this is the Swarovski part of the forum I should mention that after my frustration with the short eye relief of my Leica 10x32BA, I was very happy to find the Swarovski 8.5x42EL. I have used almost every time out with our birding group for the last couple of years. The image in the 8.5xEL was so large and bright I didn't miss the 10x.

But now that Leica and Zeiss have come out with high performace 10x42 binoculars with good eye relief, I'm happy to try them. But, I still am very happy with the 8.5x42ELs.

Rich

elkcub said:

Hi Atomic,

I've been reading your other posts on the subject and imagine you're after larger exit pupils in a smaller glass. Right? 8x25s would produce a 14.1 twilight factor compared with 12.6 for an 8x20 — representing a 13% improvement. (I find the "twilight factor" corresponds with my perceptions of brightness and ability to see at low ambient levels.)

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Greetings elkcub,

Sorry I haven't replied to this yet... been away from the house for the evening.

Yes, I'm after a larger exit pupil for 8X compact glass... both for better twilight performance as well as general purpose ease of use and "forgiveness" for misalignment. I've found 2.5mm exit pupil to be right on the edge of my own comfort level in terms of fast "setup" for acquiring an image immediately upon putting the binoculars to my eyes. 3mm or 4mm exit pupil are MUCH easier and faster for me, and much more forgiving in terms of rapid movement when suddenly moving the binoculars to acquire a new view of a different bird or a flock flying by.

However, it's not only the larger exit pupil that makes me yearn for a good pair of 7x25 or 8x25 binoculars, it's also the increase in resolution, contrast, and light gathering ability that larger objective lenses would provide. I think the manufacturers could come out with a compact binocular that would come close to 8x32 binoculars in performance while still being almost as small and lightweight as the current 8x20 compacts. Brunton ALMOST did a perfect job of this with their Eterna 8X25 binoculars, but they made a horrible mistake by limiting the field of view to an unacceptably small (at least for me) 270ft. at 1000 yds.

I still look forward to the day that a binocular manufacturer makes a 7x or 8x binocular with 25mm objective lenses and a wide field of view... I'll be one of the first customers to pick one up.

Best wishes,
Bawko

Rich,

Thank you so much for giving me short depth of field info for the 10x32BA Leicas. About a year ago I came across a birding instructor who had just gotten his 8.5x42 ELs. He saw I was using Swaro 8x30s and couldn't help jumping up and down telling me how thrilled he was to give up his own pair for the 8.5x42s. He said it was the first time in his entire life that he could actually see the whole field, since he had to use eyeglasses. Two weeks ago another friend was also beeming after getting the same binocs. I do agree with your comment about their wonderful view, so I may look at them again before committing to the 10x32s. I find them rather large, though, and the slow focusing is a challenge. Well ... nothing's perfect I guess.

I "think" Leicas allow fitting prescription lenses to the eyepieces, but haven't heard anyone comment about the feature. Maybe I got it wrong, but it would sure get past the eyeglass issue.

elkcub

You're very welcome, Elkcub.

I was planning on buying a new Swarovski 8x32EL last week but when I tried the Leica 10x42 Ultravid and Zeiss 10x42 FL I was so happy their eye relief and image quality I bought the 10x FL. With the FLs 7 diopter focuser run past infinity I can use it without my eye glasses. But, likely won't be using the FL that way.

The focuser on my 8.5x42EL is a little slow but the focuser on my 10x42 FL is a little fast. The focuser on the 8x32EL felt fine. I didn't spend a lot of time playing with it but nothing odd about hit me. At this point I feel like I'm really nit picking small problems when the binocular as a whole is so well made.

I still want a new light weight 32mm binocular. The Swarovski EL is outstanding but now I want to wait and try the new Leica and Zeiss 32s.

Rich