Problem with 10x25 ultravid (1 Viewer)

Maybe this is unusual and I had a lemon. I got a 10x25 pair from eagle last fall. I tried them out in the evening and found terrible problems with stray light. I then compared them to my old trusty 10x25 classic zeiss p coating from 1989 and ....the zeiss were clearly better and sharper. Yet when i tried a sample pair (not for sale) at a nearby camera shop during daytime viewing the zeiss clearly lacked the contrast of the leica. What do you think is going on here? I sent back the leicas. Did I have a bad pair? Anyone have similiar experience?

My first thought was that you are comparing them in two seperate lighting conditions and thus may be seeing each both in and out of their best (and potentially worst)elements. It also may be that you are accustomed to the view from your Zeiss and the Leica is just different and somewhat unfamiliar.

The only way I can think of to see if you had a lemon would be to find some way to reconstruct the same basic conditions that produced your initial observations using a different Ultravid to see if you get the same problem.

Just a guess on my part here, but I think part of your problem was trying them out for the first time in the evening when you eye pupil may have been larger than the bins exit pupil. Did you try looking through them in different directions to see if the stray light was localized? Is the 15mm eyerelief adequate for you? Or did you have to hold them slightly away from your eyes to get a perfect view? Personally I never had much truck for 10x pocket bins. To small an exit pupil and too narrow a field. 8x is much more friendly to use in a pocket format.
Bob

ceasar said:

Personally I never had much truck for 10x pocket bins. To small an exit pupil and too narrow a field. 8x is much more friendly to use in a pocket format.
Bob

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The problem with the 8x models is that all of the premium manufacturer's limit the objective lens size to only 20mm. That gives you the same 2.5mm exit pupil as the 10x25s but, the combination results in a twilight factor of only 12.65 whereas the 10x manages a TF of 15.81. Yes, the field of view is definately more compressed in the 10x models and that is a valid argument. It is also true that the 8x is theoretically going to be a bit more stable, though due to their smaller size and lighter weight this claim might be a bit suspect. What it comes down to then is; do you want a wide field or a closer look and better performance in waning light.

I know that a lot of people like the little 20mm OL minis as they allow for a truly tiny binocular. However, can't someone (other than the low-to-middle range manufacturers) recognize the greater utility that the 8x25mm format (with its TF of 14.14) would provide?

In the end I think it comes down (as do most things related to optics) to a question of personal preference. I have tried both and while my regular everyday binocular is currently an 8x25 (Pentax DCF MC II,) when I replace it (hopefully soon) I will undoubtedly choose a 10x25. I just have to make a final decision on whether I want the Leica Ultravid, Nikon LXL, Zeiss Victory, or even perhaps even a Zeiss ClassiC or Leica Trinovid.

From their standpoint the 8x20 with the 2.5mm exit pupil is the main design and works as well as it is designed to do. The 10x was probably bumped up to 25mm to maintain the same sized pupil. They were not really meant for birding so their extremely small size is a great selling point for the purpose of portability.

Weight is probably the main factor in not going up to 25mm objectives. It will add 3 or 4 ounces to the bin unless a lightweight material is used in their construction. With more glass you need more metal. A case in point is Pentax's fine 8 x 28's and 10 x 28's. They weigh in at 16.1 oz. each yet they are quite compact.
Bob

I'd have to disagree somewhat Bob. The pentax style is hardly compact compared to a folded 8x20 Ultravid.

littlu said:

Maybe this is unusual and I had a lemon. I got a 10x25 pair from eagle last fall. I tried them out in the evening and found terrible problems with stray light. I then compared them to my old trusty 10x25 classic zeiss p coating from 1989 and ....the zeiss were clearly better and sharper. Yet when i tried a sample pair (not for sale) at a nearby camera shop during daytime viewing the zeiss clearly lacked the contrast of the leica. What do you think is going on here? I sent back the leicas. Did I have a bad pair? Anyone have similiar experience?

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All pocket binoculars even the high end ones suffer more or less by stray light more than their bigger sibblings. Depending on the angle the rays of light meet the objective lenses every of those binoculars has a special point where the stray light is getting clearly visible. When you compared both 10x25s you probably met this position with the Leica by coincidence while the Zeiss would had this point at another angle. I´ve seen also what you described with all pocket binos made by Leica, Nikon, Swarovski and Zeiss and have to say that the Ultravids works comparable good in this respect. Obviously there are some special technical difficulties to prevent pocket binoculars from stray light. Perhaps because there´s not enough space for baffling.

Steve

Can't argue with that except I'd define the 8 x 20's as tiny rather than compact. The Pentax 8 x 28's roof prisms are almost as compact as Pentax's DCF MCII 8 x 25 Roof's. They are only .3" longer and .6" wider but are 5+ oz's heavier. (Info from Eagle Optics Catalog.) Most small bins with 20mm objectives are 4.0" long or less while those with 25mm objectives are about a 1/2" longer or more.
Bob

Agreed, semantics I suppose.

thanks for your fine help

eetundra said:

Agreed, semantics I suppose.

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maybe i will get another 10x25 leica

ceasar said:

Weight is probably the main factor in not going up to 25mm objectives. It will add 3 or 4 ounces to the bin unless a lightweight material is used in their construction. With more glass you need more metal. A case in point is Pentax's fine 8 x 28's and 10 x 28's. They weigh in at 16.1 oz. each yet they are quite compact.
Bob

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I don't disagree with you at all here. However, I suppose my point is that since they are already making 10x25s, there isn't any new re-tooling, or complicated logistics to be managed. All they would have to do is replace the 10x eyepeice with an 8x. (Or am I missing something?) They could still offer the 20mm models for those who want the ultimate in compactness but, then offer the 25mm model for those who would like the extra resolution, brightness, stability, etc. of the 8x power, while still maintaining an exceedingly compact design.

I really like the Pentax DCF MPs but, they do stretch a bit the idea of a compact binocular. Although they sit very nicely in a jacket pocket, I cannot, for example, slip them into my pants pocket comfortably. I can do this with many of the *x25 compacts on the market (including my DCF MC II, though it is probably right at the size/weight limit for such carrying.) Some of the higher end models (for example, the Leica Ultravid-especially in leather) absolutely disappear in a front pocket, making them VERY comfortable for carrying all day.

The eyepiece is the complicated optical piece, redesigning it is way more costly than putting a different sized objective in front or it.