Fingerprints on Zeiss 10x42 FL internal optics. (1 Viewer)

zuiko · Nov 26, 2005

Fingerprints on Zeiss 10x42 FL internal optics. (Picture)

Hi all,

Several people had posted regarding fingerprints on the prisms of their Zeiss FL binoculars. Well to my dismay I examined my sample and found a fingerprint which I have photographed to the best of my ability...

Light source was an LED flashlight. Note the dust specks around the main fingerprint; there's also some smudging to the upper right of the image from handling presumably. The view is from the objective side. Lens used to photograph is an adapted Zuiko 90mm f2 macro lens set at f2 (very shallow DOF), on a Canon 20D.

How this gets beyond QC is beyond me really. If I can see it readily with a flashlight scanned into the objective and (with some moderate difficulty) photograph it then surely QC should pick this up?

This sample is fortunately within a return window - so will be returned on Monday. There are at least two other reports of this in FL's so it may be more prevalent. Whether it makes an optical difference? Should it be there?

If you're worried your FL has a fingerprint, then don't check if the image below scares you.

Regards,
O.C

Otto McDiesel · Nov 26, 2005

They should trace the fingerprint to the worker who left it there and have them clean it.

The 10x42 FL (3 samples looked at, one of them was with me for 1 week), never did it for me - but i was impressed by the 8x42 FL. Maybe the 10x42's had QC issues...
Regardless, i am happy with my Ultravid 10x42, and there are no bread crumbs in them.

Bubbs · Nov 26, 2005

Unbelievable! I thought these things were put together in a sterile environment along with the enginneers 'gloved'....obviously not.

Good photograph.

John.

Swissboy · Nov 26, 2005

Otto McDiesel said:
They should trace the fingerprint to the worker who left it there and have them clean it.

The 10x42 FL (3 samples looked at, one of them was with me for 1 week), never did it for me - but i was impressed by the 8x42 FL. Maybe the 10x42's had QC issues...
Regardless, i am happy with my Ultravid 10x42, and there are no bread crumbs in them.

I'm one of those who reported fingerprint traces. In my case it is a 8x42 model. Fortunately, the trace is only in the side position comparable to the smudging on the picture, but more clearly a finger print.

Rico · Nov 27, 2005

Good catch, zuiko - that fingerprint is completely unacceptable. Happily, my 7x42 FL passes the flashlight inspection.

Swissboy · Nov 27, 2005

fingerprint 2

Swissboy said:
I'm one of those who reported fingerprint traces. In my case it is a 8x42 model. Fortunately, the trace is only in the side position comparable to the smudging on the picture, but more clearly a finger print.

Well, after rereading Zuiko's description how he did his demo picture, I tried it as well. I also used a LED flashlight set in front of the eyepiece. The Casio QV-R51 compact digital camera, set at close focus did the job at the first attempt. I think the fingerprint origin of the deposit is even more obvious in this sample. The bluish cast to the right is a reflection of the multi LED light source.

zuiko · Nov 28, 2005

Swissboy said:
Well, after rereading Zuiko's description how he did his demo picture, I tried it as well. I also used a LED flashlight set in front of the eyepiece. The Casio QV-R51 compact digital camera, set at close focus did the job at the first attempt. I think the fingerprint origin of the deposit is even more obvious in this sample. The bluish cast to the right is a reflection of the multi LED light source.

Incredibly, when I returned the pair photographed above, a second pair was offered in exchange. It too had fingerprints on BOTH sides similar in extent to the ones in your picture but more smudged. They were oriented toward the central flange - so at ~ 2'o'clock in the right eye and 10'o'clock in the left eye tubes viewed from the objective side.

The serial numbers of the pairs I have examined are:

302723x - first pair.

304305x - second pair.

In addition to the fingerprints (lesser extent) in the second pair; there was a glob of oil/fluid ~3-4 mm in size on a lens element ~5cm behind the objective lens.

To say I was shattered is an understatement.

Regards.

henry link · Nov 28, 2005

I've spent considerable time this morning with flashlight, reading glasses and magnifiers trying to see fingerprints inside my Zeiss FL. What I found were many little dust bits reflecting back from what gave every appearance of being the front surface of the prism. They looked to be coming from exactly the same place inside the binocular that Zuiko and Robert photographed.

Then I noticed something odd. There seemed to be a tiny twin for one of these spots on the front surface of the objective. I cleaned off the twin and the "prism" spot dissappeared also. Then I lightly touched the glass near the edge of the objective and a fingerprint appeared both on the objective and on the "prism". At just the right angle I found I could see three of these fingerprints in a line appearing just as if they were coming from other prism faces. These dust bits and fingerprints look quite convincingly like they are coming from prism surfaces inside the binocular, but they are in fact a magnified infocus reflection of the front surface of the objective, coming from perfectly clean prism surfaces. These specks can be easily missed on the objective because there they are much smaller than the reflected image of them coming from the prism. Perhaps Robert and Zuiko can try this same experiment by either cleaning the objective at the corresponding spot to where a fingerprint seems to appear on the prism or, even more convincing, add what looks exactly like a fingerprint on the prism surface by touching the front of the objective. My guess is that other binoculars with different objective focal lengths and prism designs will probably not show this same illusion.

seawatcher · Nov 28, 2005

Bet half the BF forum members are spending this evening shining flashlights into their optics. Still, keeps people off the streets I suppose.

justin2992 · Nov 28, 2005

seawatcher said:
Bet half the BF forum members are spending this evening shining flashlights into their optics. Still, keeps people off the streets I suppose.

No doubt

. My 10x32 FL has clean internals B

. By the way, an incandescent flashlight makes things much more visible than the bluish hue of an LED flashlight.

Sc0tty · Nov 28, 2005

henry link said:
I've spent considerable time this morning with flashlight, reading glasses and magnifiers trying to see fingerprints inside my Zeiss FL. What I found were many little dust bits reflecting back from what gave every appearance of being the front surface of the prism. They looked to be coming from exactly the same place inside the binocular that Zuiko and Robert photographed.

Then I noticed something odd. There seemed to be a tiny twin for one of these spots on the front surface of the objective. I cleaned off the twin and the "prism" spot dissappeared also. Then I lightly touched the glass near the edge of the objective and a fingerprint appeared both on the objective and on the "prism". At just the right angle I found I could see three of these fingerprints in a line appearing just as if they were coming from other prism faces. These dust bits and fingerprints look quite convincingly like they are coming from prism surfaces inside the binocular, but they are in fact a magnified infocus reflection of the front surface of the objective, coming from perfectly clean prism surfaces. These specks can be easily missed on the objective because there they are much smaller than the reflected image of them coming from the prism. Perhaps Robert and Zuiko can try this same experiment by either cleaning the objective at the corresponding spot to where a fingerprint seems to appear on the prism or, even more convincing, add what looks exactly like a fingerprint on the prism surface by touching the front of the objective. My guess is that other binoculars with different objective focal lengths and prism designs will probably not show this same illusion.

Its amazing how much dust becomes visible on apparently clean objectives when you shine a torch through them. My 8x32FL showed lots of tiny dust particles that weren't removed by using a blower-brush, only after using a lens cloth.

Rich.

Chris C · Nov 28, 2005

henry link said:
Perhaps Robert and Zuiko can try this same experiment by either cleaning the objective at the corresponding spot to where a fingerprint seems to appear on the prism or, even more convincing, add what looks exactly like a fingerprint on the prism surface by touching the front of the objective. My guess is that other binoculars with different objective focal lengths and prism designs will probably not show this same illusion.

Cool! If Henry's explaination holds, this would certainly explain the seemingly unexplainable high frequency of fingerprints on the FLs.

In the pair I bought and returned, the fingerprint was not a deal breaker for me since it did not affect performance as far as I could perceive. However, in both pairs of FL's I've looked through, there were visible specks on the image when viewing through the business end.

In retrospect, I'm curious whether these were exterior dust specks magnified by the unusual optical design of the FLs or if they were truly internal. Can Henry and others create visible, well defined specks on the image caused by dirt or lint on the objective or ocular? If so, this would be a rather unfortunate property of the FLs in my mind. To conserve coatings, I refrain from cleaning my bins until they are quite lint speckled and I would be quite annoyed to have to contend with keeping field glasses spotless...

Cheers,
Chris C.

Swissboy · Nov 28, 2005

Fingerprint is still there

henry link said:
I've spent considerable time this morning with flashlight, reading glasses and magnifiers trying to see fingerprints inside my Zeiss FL. What I found were many little dust bits reflecting back from what gave every appearance of being the front surface of the prism. They looked to be coming from exactly the same place inside the binocular that Zuiko and Robert photographed.

Then I noticed something odd. There seemed to be a tiny twin for one of these spots on the front surface of the objective. I cleaned off the twin and the "prism" spot dissappeared also. Then I lightly touched the glass near the edge of the objective and a fingerprint appeared both on the objective and on the "prism". At just the right angle I found I could see three of these fingerprints in a line appearing just as if they were coming from other prism faces. These dust bits and fingerprints look quite convincingly like they are coming from prism surfaces inside the binocular, but they are in fact a magnified infocus reflection of the front surface of the objective, coming from perfectly clean prism surfaces. These specks can be easily missed on the objective because there they are much smaller than the reflected image of them coming from the prism. Perhaps Robert and Zuiko can try this same experiment by either cleaning the objective at the corresponding spot to where a fingerprint seems to appear on the prism or, even more convincing, add what looks exactly like a fingerprint on the prism surface by touching the front of the objective. My guess is that other binoculars with different objective focal lengths and prism designs will probably not show this same illusion.

Unfortunately, the finger print in my FL is still present after all the cleaning. I would have been more than happy if the whole thing would have been an optical illusion! I originally discovered it not by applying Zuiko's method, but by having the sunlight shine in from the objective side and myself also checking the insides through the objective.

zuiko · Nov 28, 2005

henry link said:
I've spent considerable time this morning with flashlight, reading glasses and magnifiers trying to see fingerprints inside my Zeiss FL. What I found were many little dust bits reflecting back from what gave every appearance of being the front surface of the prism. They looked to be coming from exactly the same place inside the binocular that Zuiko and Robert photographed.

Then I noticed something odd. There seemed to be a tiny twin for one of these spots on the front surface of the objective. I cleaned off the twin and the "prism" spot dissappeared also. Then I lightly touched the glass near the edge of the objective and a fingerprint appeared both on the objective and on the "prism". At just the right angle I found I could see three of these fingerprints in a line appearing just as if they were coming from other prism faces. These dust bits and fingerprints look quite convincingly like they are coming from prism surfaces inside the binocular, but they are in fact a magnified infocus reflection of the front surface of the objective, coming from perfectly clean prism surfaces. These specks can be easily missed on the objective because there they are much smaller than the reflected image of them coming from the prism. Perhaps Robert and Zuiko can try this same experiment by either cleaning the objective at the corresponding spot to where a fingerprint seems to appear on the prism or, even more convincing, add what looks exactly like a fingerprint on the prism surface by touching the front of the objective. My guess is that other binoculars with different objective focal lengths and prism designs will probably not show this same illusion.

Hi Henry,

Unfortunately no this does not apply to either pair I have examined.

The objectives were spotless in both cases and especially in the second case which was 'virginal' (ie. box had not been opened).

The prints are a real and not virtual image and you can see from the photograph that the print is encroaching at least 40% into the field and represents real oily matter. It came into focus only as the plane of focus caught it and did not disappear or move when viewed from a different angle.

Moreover the second pair definitely had an oil globule which even the salesperson saw quite easily.

Regards.

Chris C · Nov 28, 2005

zuiko said:
Hi Henry,

Unfortunately no this does not apply to either pair I have examined.

The objectives were spotless in both cases and especially in the second case which was 'virginal' (ie. box had not been opened).

The prints are a real and not virtual image and you can see from the photograph that the print is encroaching at least 40% into the field and represents real oily matter. It came into focus only as the plane of focus caught it and did not disappear or move when viewed from a different angle.

Moreover the second pair definitely had an oil globule which even the salesperson saw quite easily.

Regards.

:storm: Bummer! Sorry to hear that zuiko and Robert! zuiko, I'll be interested to hear about your longer term impressions of the ultravid, as I'll probably spring for a pair of 10x's eventually. The FLs are remarkable in ways both good and bad, I suppose...

Cheers,
Chris C.

zuiko · Nov 29, 2005

Chris C said:
:storm: Bummer! Sorry to hear that zuiko and Robert! zuiko, I'll be interested to hear about your longer term impressions of the ultravid, as I'll probably spring for a pair of 10x's eventually. The FLs are remarkable in ways both good and bad, I suppose...

Cheers,
Chris C.

Hi Chris,

I'll post my short term experience+comparison with the notes I have on the FL, when I've had an equal time with the Ultravids; and if I'm still around, a longer term review after a few weeks/months.

Best wishes.

Swissboy · Nov 29, 2005

Swissboy said:
Well, after rereading Zuiko's description how he did his demo picture, I tried it as well. I also used a LED flashlight set in front of the eyepiece. The Casio QV-R51 compact digital camera, set at close focus did the job at the first attempt. I think the fingerprint origin of the deposit is even more obvious in this sample. The bluish cast to the right is a reflection of the multi LED light source.

I had thought my picture was taken the same way as Zuiko's. But, apparently, the illumination is from different sides. I my picture, the flashlight is shining in from the eyepiece side, which makes the finger print stand out more.

henry link · Nov 29, 2005

Robert,

I was about to post a question to you about that. Shining the light through the eyepiece appears to have the advantage of not producing the objective reflection that can mimic a dirty prism. Sorry to have given you some false hope about your fingerprint, but if it is any consolation I am 100% certain that the print in your photo will have no effect at all on the image quality. It happens at a place in the optics where it is very very far out of focus and could never be seen as a spot or shadow when looking through the eyepiece. I have a binocular which arrived with a fingerprint on the field lens of the eyepiece. Until I cleaned it off that looked like a large almost infocus fingerprint superimposed on the image when I looked through the eyepiece, impossible to ignore. In your case the worst effect would be a virtually unmeasurable and completely invisible reduction in contrast. Since the other barrel has no fingerprint you can, if you choose, switch back and forth with one eye to try to see a difference. But even if you see a difference, I guarantee it won't be from the fingerprint.

WmCCO-5 · Nov 29, 2005

Swissboy, (and for all who think that they may have FINGERPRINT issues with the optics in their FL's),

Hello. You and Zuiko posted very nice photographs...my hat is off to both of you. Unfortunately I am without my camera for a few days, (as my wife has taken it to a horse show), so I will not be able to provide a similar photograph.

Swissboy, an examination of my 8x42FL revealed the same exact anomoly in the left tube as depicted in your photo. In addition, my blemish is significantly larger than yours.

Now for the GOOD NEWS. The anomoly present in my pair is NOT on the (Abbe-Koenig prism) glass surfaces, it is on/in the interior non-glass surface of the prism housing or tube. My best guess is that it is a file mark or fingerprint left from the assembly person's effort to remove excess material, ( plastic, glue or other),which is a GOOD thing. I suspect that a large number of FL's show the same thing. If we had silver or other mirrored surfaces it would probably not be visible. It is cosmetic only and is positively of NO CONSEQUENCE optically, mechanically or structurally. We could undoubtedly find a similar cosmetic flaw in any binocular if we disassembled several samples of each. With the Abbe-Koenig prism we are simply better able to see the interior of the housing...take a look.

With regard to Zuiko's photograph, it appears to me that he, in fact, has a slight fingerprint or smudge on a glass surface, somewhere. I hope the issue is resolved to his satisfaction. I believe that I would possibly give Zeiss a chance to clean them up if they were mine.

Like many here, I'm still in love with my FL's...unfortunately, like all binoculars, including the Leicas and Swaros, they were exposed to potential or actual human error during assembly.

My best,

Bill

Otto McDiesel · Nov 29, 2005

Sheesh,

They ought to stop eating gulash and assembling binoculars in the same time...

Fingerprints on Zeiss 10x42 FL internal optics. (1 Viewer)

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