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Victory Pockets: Terrible quality control (1 Viewer)

tenex

reality-based
The Victory Pocket 8x25 seems like a great compact travel binocular, bright, solid, smooth focusing -- although nearly 2 turns of travel, and eye relief so high I can barely use it. (An increasingly common problem today.)

But I've received two defective units in a row. The first had obvious, multiple blemishes in the coating of one ocular. The second had something on it also, but it cleaned off... and then I found a thin strip/loop of metal (about 1/4", 6mm) protruding into one barrel from machining the baffling. That will be fun when it falls off and gets onto a lens. How can Zeiss possibly have such terrible quality control? This is a premium ($750) bino made in Japan, not the third world.

Incidentally, focusing on a map on the wall, I saw something odd in the optics also. The resolution wasn't as good near the bottom of the field as near the top -- and the same remained true with the bino upside down! What misalignment would cause that? Don't know whether the first unit had the same problem, didn't check... but I'm not really inclined to try a third. Caveat emptor!
 
I thought that Zeiss Victory Binoculars were all made in Germany. Although I do recall that the recently discontinued Zeiss Victory 8x20 was made in Hungary.

Bob
 
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Incidentally, focusing on a map on the wall, I saw something odd in the optics also. The resolution wasn't as good near the bottom of the field as near the top -- and the same remained true with the bino upside down!

Do you know if you have astigmatism? Astigmatism is the usual suspect for this kind of behavior.
 
I thought that Zeiss Victory Binoculars were all made in Germany. Although I do recall that the recently discontinued Zeiss Victory 8x20 was made in Hungary.

Bob

Hi Bob

You are correct in that the previous Victory Compacts were made at the Zeiss factory in Hungary, but the new ones are made in Japan. The other Victories are all made in Germany.

Lee
 
I saw something odd in the optics also. The resolution wasn't as good near the bottom of the field as near the top -- and the same remained true with the bino upside down!

If the phenomenon didn't move to the top when you turned the binos upside down then logically one would deduce that the problem is not in the bino, and as Peter points out, this definitely sounds like astigmatism.

Lee
 
The effect is pretty obvious in this 8x25 VP. When I focus on something in the center I can move the bino around and that target is still acceptably sharp at the top or sides of the field, but not at the bottom. If I try to focus on what's near the bottom of the field it seems difficult to get it perfectly sharp at any setting. Results are the same with the bino reversed.

The thing is I've never noticed this using other binos. I don't see it at all, or perhaps just barely, in the 10x32 UVHD+ I have on hand now to compare. If it's my own astigmatism, can one bino show this effect more prominently than another, and why?
 
Field curvature or other aberrations.

Astigmatism is pretty obvious if one looks at a bright star. It appears as a short or longer line.

An optician will quickly give an opinion.
 
In my experience smaller exit pupils exaggerate visual problems. A larger exit pupil gives the brain more to work with. The brain will piece together an image and do the best it can. Give it more info and it will put together a better image.

But yes, in this case it sounds like the eyes are at fault. Welcome to middle age??

Of course this has nothing to do with the QC of the binos in question. That doesn't sound good at all.
 
I don't see it at all, or perhaps just barely, in the 10x32 UVHD+ I have on hand now to compare. If it's my own astigmatism, can one bino show this effect more prominently than another, and why?

Yes, it can: it depends on bino's field curvature, astigmatism and other distortions.
 
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Incidentally, focusing on a map on the wall, I saw something odd in the optics also. The resolution wasn't as good near the bottom of the field as near the top -- and the same remained true with the bino upside down! What misalignment would cause that? Don't know whether the first unit had the same problem, didn't check... but I'm not really inclined to try a third. Caveat emptor!

I don't think this is related to astigmatism in your eye. That would have the same effect at the 6:00 and 12:00 positions of the binocular's field edge. I've observed this same effect in most binoculars and after some experimenting determined that it is caused by variations in exit pupil vignetting due to unconscious differences in way the eyeball rotates when looking in different directions.

The way the eyeball rotates looking down seems to naturally cause less exit pupil vignetting than looking in other directions. That might sound like a good thing, but less exit pupil vignetting actually degrades edge of field aberrations. A highly vignetted exit pupil at the edge (enough to make the exit pupil smaller than the eye's pupil) improves the sharpness at the edge by by stopping down the eye and increasing its depth of field

You can induce an improvement at the 6:00 position in any binocular by consciously moving your whole eye down a little toward the bottom of the field before you rotate your pupil in that direction. Or try moving your eyeball up and down after you rotate to search for the sharpest image at the edge. The lowest aberrations will occur just before you experience a blackout coming from the top of the field as the vignetting approaches 100%.
 
Henry:

I don't think this is related to astigmatism in your eye. That would have the same effect at the 6:00 and 12:00 positions of the binocular's field edge

I believe that would be true only for some forms of regular astigmatism, but not for oblique or irregular astigmatism.

I've observed this same effect in most binoculars and after some experimenting determined that it is caused by variations in exit pupil vignetting due to unconscious differences in way the eyeball rotates when looking in different directions.
The way the eyeball rotates looking down seems to naturally cause less exit pupil vignetting than looking in other directions.

That's an interesting possible explanation. I'll try to test it as you suggest below
(I hope the OP will test your explanation too and will let us know if the effect vanished). If your explanation is true that would mean that the effect is a general one, which begs the question why it was almost never reported.

You can induce an improvement at the 6:00 position in any binocular by consciously moving your whole eye down a little toward the bottom of the field before you rotate your pupil in that direction

Peter.
 
I find that many binoculars give me a good view at the 6 o'clock position closer than the focus point at the centre.
I thought this was due to field curvature, but this may be due to both field curvature and different amounts of vignetting.
I use this to give clear views without having to refocus.
Many binoculars give me a wider horizontal view with good definition than vertically.
I thought this was by design, but it could be due to different eyeball movement.
 
I find that many binoculars give me a good view at the 6 o'clock position closer than the focus point at the centre.

I have experienced the same effect with some binos, and I still believe it's due to a combination between bino's field curvature and my eye astigmatism.
 
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Henry:

Regarding your explanation, the OP has noticed this effect in an 8x25 but not in a 10x32---these two binos basically have the same EP, so what makes your conjecture valid for one but not the other? (maybe their different baffling and aperture stops?). Also, I have noticed that in my case this effect is more pronounced for one of my eyes, and therefore I still believe that my astigmatism plays a role in explaining it, at least partly.

Peter
 
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In my experience smaller exit pupils exaggerate visual problems. A larger exit pupil gives the brain more to work with. The brain will piece together an image and do the best it can. Give it more info and it will put together a better image.

But yes, in this case it sounds like the eyes are at fault. Welcome to middle age??

Of course this has nothing to do with the QC of the binos in question. That doesn't sound good at all.

I don't understand what you mean when you say "A larger exit pupil gives your brain more to work with." Could you explain your reasoning.

Thanks, and clear skies, Alan
 
I don't think I have much astigmatism, though I am pushing 60 and slightly myopic. Stars are still nice pinpoints.

This odd 6:00 effect occurs at both near and far focus, in bright or dim light. It's not just field curvature because refocusing can't quite correct it. Whatever the reason may be for seeing it in the VP 8x25 and not other binos, I think Henry is on the right track, it has to do with the eye looking downward. I now find that the angle of my head makes a difference: I had naturally been looking down to examine the bottom of the FoV, or tilting my head up along with the bino to view the same target as it approached the lower edge, so I wound up looking down at it. If instead I tilt only the bino upward, so my eyes are still looking straight ahead (or even up a bit if I also tilt my head forward), the lower edge stays pretty sharp. Of course this is not what one normally does.
 
At night, the larger the exit pupil, the worse the star images are for me.
But the images are brighter with larger exit pupils.

People with small amounts of astigmatism do better with smaller exit pupils down to 2mm or 1mm or less if their eyes are free of other imperfections. Usually using telescopes for very small exit pupils.
Often correcting glasses don't need to be used giving larger fields with small eye relief instruments.
 
If instead I tilt only the bino upward, so my eyes are still looking straight ahead, the lower edge stays pretty sharp

I believe that if you tilt the bino upward, as you say above, you are looking thru the upper part of the EP, not its lower part. In fact this is what I do to avoid glare in the lower part
of the EP.
 
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