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Old Tuesday 29th August 2006, 00:51   #1
01Foreman400
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Question Glare Question?

I just got a pair of Zeiss Victory FL 8x42 today and when I'm using them and moving I noticed a half moon glare at the bottom. There was no sun out. Is this normal? I've never had this problem with my Nikon Monarch's

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Darrell
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Old Tuesday 29th August 2006, 05:29   #2
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Sounds (looks?) like a form of blackout (white out here?). Make sure you have your IPD set correctly and your eyecups positioned correctly. When it happens again move the binoculars closer to your eye or further away to see if it disappears. Does it happen if the sun is behind you, in front of you or all the time?
Bob
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Old Tuesday 29th August 2006, 12:47   #3
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Red face

Quote:
Originally Posted by ceasar
Sounds (looks?) like a form of blackout (white out here?). Make sure you have your IPD set correctly and your eyecups positioned correctly. When it happens again move the binoculars closer to your eye or further away to see if it disappears. Does it happen if the sun is behind you, in front of you or all the time?
Bob

Thanks for responding Bob. I have tried moving the eyecups at different heights moving them away from my face. I have already adjusted the IPD. It was a cloudy day yesterday it even happened at dusk. It happens all the time. I even let me wife look through them (I don't think she has ever used binoculars) and asked her how they looked and she said there was a half moon halo at the bottom. At that point I figured it wasn't just me.


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Darrell
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Old Tuesday 29th August 2006, 13:27   #4
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Darrell,

Unfortunately you've had the misfortune of noticing an imperfection in the internal baffling design of the FL on your first day out with it. The "half moon" you see at the bottom of the field is actually two half moons superimposed over each other. They are out of focus reflections caused by the relatively bright light of the sky reflecting off the edge of the objective cell (mostly from the spacer between the air spaced elements) and a somewhat brighter second reflection coming from the edge of the focusing element cell. Properly sized knife edged baffles installed at the rear of those cells would have completely eliminated the reflections. You can see these crescent shaped reflections at the edge of the exit pupil if you move your eye back from the eyepiece when you see the "half moons" and look at the edge of the small bright circle formed by the exit pupil.

In the field these reflections are actually seldom visible. It takes a particular set of lighting conditions. It's most likely if you are looking into a dark area on a cloudy day or at twilight with open sky above you. Your eye needs to be open quite wide to catch a reflection from beyond the edge of a 5.2mm exit pupil. In bright sunlight the reflection is likely to fall harmlessly on the iris. If it's any consolation I've owned the 8x42 Fl's for about two years. I've looked through them thousands of times and almost never notice the problem. I consider it a minor annoyance since I know it could have been avoided in the design, but it's really not too bad and far from a deal breaker in a binocular with so many other virtues.

I should add that unbaffled reflections from objective cells are very common in binoculars. If you can see them under some conditions at least you know the objective is relatively unvignetted. Not seeing them isn't necessarily even a good sign. Some binoculars have prisms so undersized that they vignette the edge of the exit pupil. That takes care of the reflection problem but also effectively reduces the aperture of the objective.

Henry

Last edited by henry link : Tuesday 29th August 2006 at 14:19.
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Old Tuesday 29th August 2006, 23:29   #5
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The phenomena described here can also be produced if you are looking at a horizon nearly splitting the view horizontally where the bottom of the view is dark (woodland, shadows, a dark hillside material like coal grains) and the sky has lots of diffuse light either from the sun setting behind the hill you are facing, or a cloudy, misty sky with any sun location. In this case if the bottom of the view is dark and there is substantial light in the sky you can clearly see stray light half-moons reflecting at a large angle off of the interior into the bottom view. This stray light isn't always obvious in the more brightly lit half of the view because it is a soft ghostly kind of light, but in the dark areas of the view it can seem like a whispy kind of half circle image. The baffling on Zeiss binoculars should be excellent but I don't know if a full-out secondary cone baffle is used in the model of bin you are describing.

In the 15x60BGA*T I've seen this effect at noon on a really cloudy day where it is impossible to exactly locate the sun except to know it is overhead. It seems to occur more often with bins that have an objective lens set out near the front of the bin housing as opposed to bins with the objectives set back and behind a protective clear lens (assuming the bin doesn't have a conical tube-inside-of-a-tube style of baffling which seems to totally cancel all stray foggy light). There are a few military glasses reknown for having super double baffling or extreme multiple baffles that I use as standards whenever people start complaining that everyone at the ranch is having this kind of lightly lit half circle lower half-of-view problem.

Sometimes the problem can occur in reverse. Once there is a complete snow cover, if there is a day with very low cloud cover it can be difficult to look into a dark stand of (now barren) thick forest. The very dark band of thick forest in the middle of the view is sandwiched between a diffuse light source on the top of the view and totally reflective snow cover on the bottom of the view. All sorts of big white clouds can move around in the middle of the view and most have rounded tops or bottoms indicating they are really stray light objective lens reflections. The only thing that works on those days is a specially outfitted spotting scope with a 12 long "sun" shield that sticks off the front of the scope and cuts out almost all stray light to the objective. Full diffuse light is one of the most difficult phenomena to tame in a binocular.

Quote:
Originally Posted by henry link
Darrell,

Unfortunately you've had the misfortune of noticing an imperfection in the internal baffling design of the FL on your first day out with it. The "half moon" you see at the bottom of the field is actually two half moons superimposed over each other. They are out of focus reflections caused by the relatively bright light of the sky reflecting off the edge of the objective cell (mostly from the spacer between the air spaced elements) and a somewhat brighter second reflection coming from the edge of the focusing element cell. Properly sized knife edged baffles installed at the rear of those cells would have completely eliminated the reflections. You can see these crescent shaped reflections at the edge of the exit pupil if you move your eye back from the eyepiece when you see the "half moons" and look at the edge of the small bright circle formed by the exit pupil.

In the field these reflections are actually seldom visible. It takes a particular set of lighting conditions. It's most likely if you are looking into a dark area on a cloudy day or at twilight with open sky above you. Your eye needs to be open quite wide to catch a reflection from beyond the edge of a 5.2mm exit pupil. In bright sunlight the reflection is likely to fall harmlessly on the iris. If it's any consolation I've owned the 8x42 Fl's for about two years. I've looked through them thousands of times and almost never notice the problem. I consider it a minor annoyance since I know it could have been avoided in the design, but it's really not too bad and far from a deal breaker in a binocular with so many other virtues.

I should add that unbaffled reflections from objective cells are very common in binoculars. If you can see them under some conditions at least you know the objective is relatively unvignetted. Not seeing them isn't necessarily even a good sign. Some binoculars have prisms so undersized that they vignette the edge of the exit pupil. That takes care of the reflection problem but also effectively reduces the aperture of the objective.

Henry
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Old Tuesday 29th August 2006, 23:37   #6
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Talking

Great answer Henry! I had a feeling you'd come through on this. As usual your explanation is both precise and concise. Good follow up also KSBird! I gave this thread a 5 rating!
Bob

Last edited by ceasar : Tuesday 29th August 2006 at 23:41.
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Old Wednesday 30th August 2006, 13:23   #7
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Thanks for all the nice stars, Bob. I'm almost speechless.;-)

I played around with this a little more today. I set up a tripod near a window and mounted various binoculars on it. I pointed the binoculars down toward a dark floor beneath the window and observed the reflection from the objective edge directly through the eyepiece and by looking into the binocular innards with a magnifier through the eyepiece.

Nearly every binocular I tried showed a "half moon" across the bottom of the field, some brighter than others. In looking directly through the binoculars large exit pupils have the advantage since the reflection is at the edge of a larger circle and therefore less likely to enter the eye. Some binoculars were much worse than the Zeiss FL. The absolute worst was a Steiner 6x30 which has a smooth highly reflective tube between the objective and the prism (what were they thinking?). The best performers in the test were the Nikon 8x30 EII and its predecessor E models which all use the same objective cell design. The big secret in these binoculars is a 5 cent piece of thin stamped metal formed into a shallow cone about 5mm deep and attached to the rear of the objective cell. It's sized and shaped to do a pretty good job of masking off the reflection of the cell edge. There is no baffling at all between the objective cell and the prism shelf in these binoculars. The interior is just painted flat black. In contrast the 8x32 SE has an impressive looking baffled tube between the objective and the prism. This should help generally with light scatter and improve contrast, but it doesn't do as much to mask the objective edge, so the SE didn't do quite as well in this test as the E and EII. For this particular problem elaborate interior baffling is not the solution. Just one properly designed and placed baffle is all that's needed.

Last edited by henry link : Wednesday 30th August 2006 at 13:36.
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Old Thursday 31st August 2006, 01:30   #8
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Henry,

After swearing off more binocular purchases I came across a mint 8x30E yesterday at a price I simply couldn't refuse. So much for self control. It matches the appearance and performance of my 10x35E. Do these two binoculars use the same eyepieces by some chance?

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Ed
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Old Thursday 31st August 2006, 01:58   #9
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I agree completely with you Henry, the Hensoldt DF and Fero D16 and Nikon E and E II 8x30s, the VOP and Nippon Kogaku Mikron 6x30 and the Jason Statesman 7x50 and 7x35 have these cone within a cone "baffles" I alluded to earlier and they seem to reduce the stray light coming from large angle objective lens edge reflections of light the best especially if these internal cones have baffle "steps" built into them. Actually the Hensoldt DF seems to be the best of all. A few reviewers like Holger Merlitz also don't understand why this "technology" isn't used much more often.

Here what it would require to achieve: The outer tube for the objective back to the prism would have to be slightly larger, an attachment would have to be developed in front of the prism (or with the use of one flat field stop style baffle - behind the objective lens) like a thread for the cone-shaped tube-within-a-tube to screw into, or perhaps a flat surface mount with 2 clips ..., and the internal cone itself. The Hensoldt DF/D-16 and VOP binoculars are waterproof and pretty much bulletproof as they were the NATO or Czech standard field binoculars for many years.

There might have been a very few additional warranty problems with the Nikon EII binocular "internal cones" coming loose and so for some reason Nikon stopped using these cones. Hensoldt/Zeiss also stopped using them after the Fero D16 model as well, VOP technology may be in use by Meopta but I can't tell because I don't see many Meopta bins and Jason/Bushnell hasn't made a bin like the Statesman models for many years (so I know of 8 modern binoculars that used these cones, if there are more I would appreciate it if anyone would tell me the models so I can collect them). For something so effective, it is a shame they aren't used any more. If Henry or I ever run an optics company we can be sure to specify a Chinese model porro prism binocular using this low technology (although there is no reason why this shouldn't work on a roofer as well). Thanks to Henry for doing the legwork to verify that most binoculars could use a dose of this kind of cone baffling.

Quote:
Originally Posted by henry link
Thanks for all the nice stars, Bob. I'm almost speechless.;-)

I played around with this a little more today. I set up a tripod near a window and mounted various binoculars on it. I pointed the binoculars down toward a dark floor beneath the window and observed the reflection from the objective edge directly through the eyepiece and by looking into the binocular innards with a magnifier through the eyepiece.

Nearly every binocular I tried showed a "half moon" across the bottom of the field, some brighter than others. In looking directly through the binoculars large exit pupils have the advantage since the reflection is at the edge of a larger circle and therefore less likely to enter the eye. Some binoculars were much worse than the Zeiss FL. The absolute worst was a Steiner 6x30 which has a smooth highly reflective tube between the objective and the prism (what were they thinking?). The best performers in the test were the Nikon 8x30 EII and its predecessor E models which all use the same objective cell design. The big secret in these binoculars is a 5 cent piece of thin stamped metal formed into a shallow cone about 5mm deep and attached to the rear of the objective cell. It's sized and shaped to do a pretty good job of masking off the reflection of the cell edge. There is no baffling at all between the objective cell and the prism shelf in these binoculars. The interior is just painted flat black. In contrast the 8x32 SE has an impressive looking baffled tube between the objective and the prism. This should help generally with light scatter and improve contrast, but it doesn't do as much to mask the objective edge, so the SE didn't do quite as well in this test as the E and EII. For this particular problem elaborate interior baffling is not the solution. Just one properly designed and placed baffle is all that's needed.
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Old Thursday 31st August 2006, 13:59   #10
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Quote:
Originally Posted by ksbird/foxranch
....There might have been a very few additional warranty problems with the Nikon EII binocular "internal cones" coming loose and so for some reason Nikon stopped using these cones.....
ksbird,

The Nikon "cones" (I hesitate to call them cones because they are so shallow) are built into the objective cells and really can't come loose. If you are willing to unscrew an objective from one of these you will see what I mean. I wouldn't be surprised if your old Mikron uses exactly the same objective cell as the E/EII. The SE is completely different. It has a grooved retaining ring at the back of the objective cell which isn't quite as effective at masking the edge reflections.

A long baffled cone between the objective and the prism shelf will only suppress the objective edge reflections if the front of it is sized and positioned correctly. The shallow 5mm cone in the Nikons really works just as well for this as a long cone would. Of course, cones between the objectives and the prisms can't be used in binoculars with internal focusing where focusing elements move back and forth in this area. A shallow cone or just a properly sized knife edged baffle at the back of the objective cell (and the focusing lens) should be all that's needed to cover the edge reflections. According to the cut-away drawing of the the Zeiss 42mm FL I downloaded from the Zeiss website the rear of the objective cell actually does act as a baffle, but it's inside diameter is just not quite small enough to completely mask the shiny edge of the cell.

Henry

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Old Friday 1st September 2006, 00:42   #11
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After using Monarch's for 3 years and not having a single problem with them I just couldn't keep the FL's I returned them today. I will be going fo the Swarovski EL's next. I believe something was wrong with the pair I got. I called Zeiss and they told me to ship them back to Zeiss and they would fix them or give me a new pair. If they did fix them I would have paid retail price for refurbs. Not the best in the customer service department if you ask me.

Darrell
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Old Friday 1st September 2006, 13:31   #12
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Darrell,

I know we all have different priorities when it comes to binoculars, but I do believe you may be fixing on a minor problem as a litmus test. I don't think your particular pair of FL's was defective for the reasons you've described. The FL is just not the best at masking glare from the edge of the objective. However, it's really not much worse than most other binoculars and this is a very occasional problem, seen only under very specific lighting conditions. I also noticed this reflection in my first days of using the FL, but I didn't consider it significant and after two years I haven't changed my mind. Far more important to me is that the 8x42 FL represents the state of the art in several major optical categories like light transmission, color accuracy, freedom from chromatic aberration and center of the field sharpness. You may find that you prefer the Swarovski 8.5x42 EL (an excellent binocular overall) but, IMO, it's not quite as good as the Zeiss in any the above categories. BTW, I can see some glare through my EL's under the same lighting conditions that cause it in the FL. The reasons are the same, an unbaffled objective edge, but there is somewhat less visible glare in the EL than the FL. I know it seems reasonable to expect total perfection from binoculars that cost $1500-2000, but I have yet to see it.

Henry
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Old Friday 1st September 2006, 14:54   #13
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Henry,
Somewhere in another website (I believe it was in another galaxy, long, long ago.) I read that man's object to achieve perfection in binocular construction was ultimately doomed to failure because of the inherent difficulty in coordinating the passage of light rays simultaneously through four sets of lenses and and a various variety of prisms through two OTA's at the given focal lengths of F4 into two differing eyes.

Binoculars are like quoits. Closeness counts!

Bob
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Old Friday 1st September 2006, 19:37   #14
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Quote:
Originally Posted by ceasar
Henry,
Somewhere in another website (I believe it was in another galaxy, long, long ago.) I read that man's object to achieve perfection in binocular construction was ultimately doomed to failure because of the inherent difficulty in coordinating the passage of light rays simultaneously through four sets of lenses and and a various variety of prisms through two OTA's at the given focal lengths of F4 into two differing eyes.

Binoculars are like quoits. Closeness counts!

Bob
You guys talk funny.

Last edited by elkcub : Friday 1st September 2006 at 23:24.
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Old Monday 18th September 2006, 14:07   #15
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Thumbs up

Thanks for all the replies. I got my Swarovski EL's 8.5x42 last Thursday and went on a 3 day hunting trip and they are great. The first thing I did was stand on my back deck (the same place I had the glare problem with the Zeiss 3 days in a row) with no glare problems at all.

Darrell
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