binoculars by Ernst Leitz 7X50

[LLOYDY]

I was hoping your members would be able to help regarding a pair of binoculars which belonged to my late Grand Father. He told me they were German U Boat Glasses. They are with case and in good condition however the rubber around the eye cup did split when I was asked for the number by the Zeiss factory when I wrote to them for information.
The number 455160 7x50 beh is stamped on the frame. I remember the glasses use to contain a perfect silver leaf in one of the lenses however this has started to fade. I am especially interested in the silver leaf in one of the lenses as no one I have asked has ever heard of this. Also I would be interested if it is possible for repairs to both the rubber and silver leaf can be made? Many thanks for any information. LLOYDY

[Zeissure]

binoculars by Ernst Leitz 7X50

if you can, post some pictures for helping you, thanks

[LLOYDY]

Hi I have tried to upload however it will not complete because a secuity token is missing? I do not understand what this means ..any ideas? Cheers LLOYDY

[LLOYDY]

if you can, post some pictures for helping you, thanks

Hi,Managed to create a link with photos. It would be great if you could help. Any problems with the link let me know. Cheers LLOYDY

https://twitter.com/MartinL29948994/...37806023512064

[matello]

Hi Martin,


Regarding the binoculars - these are not Zeiss but E.Leitz production.
Serial number (as I read it) is 45516X
Those were made in 1944.

Regarding the "silver leaf" - lenses are glued together in layers. Sometimes the glue between two layers "gives in" and as a result the lenses are not glued together in that spot. To put it simply the glueing between the lenses in this spot - "leaf" - is no more present. It does not affect the vision and looking through you will not see it.

[LLOYDY]

Hi, Many thanks for your reply. The information that they were made by E.Leitz was confirmed by Zeiss so thanks for the confirmation. I did not know a date however so that is more great information. I found it very interesting you describing the lens construction as I have written to a number of places enquiring about this and have had no luck. Just to be clear, was there ever a silver leaf placed in the lens or is it just a distortion as a result of the glue failing? As a child I do remember the "leaf" being complete and again, you are correct, it does not affect the vision.
Do you also know whether the rubber can be repaired or replaced and if a "leaf" was present, can that be restored as well?
I have not been able to find out how my Grandfather came about the binoculars.I am aware he served in the army during WW1 in France but we have not been able to locate any of his records for WW2. Many thanks for replying I do very much appreciate your help. Cheers LLOYDY

[matello]

Hi,

Judging by the pics I do not see any damage to the rubber. However, the weakest spot is the joint between the upper rubber amor and the eye-cups. If this is broken, I guess the only solution is to glue it. No replacements are available.
Furthermore, regarding the "leaf" probably it could be fixed... but that would require to dissasemble whole binoculars. But given the fact that those are navy issue binoculars, these have somewaht more complex construction. I personally would not attempt to "fix" that. This "leaf" is present in many examples and it does not affect the quality of the vision and this is another reason why I would not recommend doing anything about it.
There was never ever any "silver leaf" intentionally placed in between the lesnes.

Attached is an example of 10x80 DF with simmilar "leafs".

[Lauritz]

What you see as a leaf I see as fungus.

If you want to preserve the binos for the future, it has to be removed. Also the sight picture will become clearer.

Nice binoculars, in a nice condition for the age. The rubber and case are a bonus for collectors.

[LLOYDY]

Hi,
Once again many thanks for your brilliant explanation and advice. I have asked and written to so many people/organisations without finding out anything more about the lens or the possibility of repairing the binoculars. Many many thanks. Unfortunately like I think I may mentioned, the rubber did split when I pulled it back to obtain the number for the Carl Zeiss company I wrote to in Yena, Germany, which was very annoying as it appeared to be in perfect condition until that point. My Grandfather would have been upset as I was only ever allowed to hold them in his presence. I would love to find out how he got hold of them but...... Once again thank you very much for taking the time to write. Best Wishes
LLOYDY

[Lauritz]

I forgot: the rubber is synthetic and virtually impossible to repair nicely.
3M and similar companies have products that are glues for these rubbers, but considering the age of it I am unsure about the result. Can work decently well, can turn to disaster.

Buna ( Nitrile) or similar is the material they used.

Blc is the code for Zeiss.

As your grandfather cherished them, I personally would have them serviced by somebody competent.

I find the ocular protectors interesting.
(Most binos from this era have a Bakelite or leather ocular protector.
On this there is the word ‘Benutzer’ which is German for ‘user’.)

[globbitz]

Mirror-like 'flowers' or 'leaves' are not fungus.

What you see as a leaf I see as fungus.

If you want to preserve the binos for the future, it has to be removed. Also the sight picture will become clearer.

Nice binoculars, in a nice condition for the age. The rubber and case are a bonus for collectors.

Lauritz,

I totally disagree with your opinion (above). The mirror-like effect is not fugus. It's indicative of a vacuum 'bubble' where the cemented lenses have de-laminated in that area of the lens. Similarly you will have a mirror, but often with an additional 'rainbow' effect if the de-lamination occurs from the edge of the lens doublet.

I would suggest that it's not a serious cause for concern at all. It's literally a reflection of the binocular's age, materials, production, and handling (heating and/or shock).

I agree that the presence of the bubble(s) will, however, cause a small reduction in the amount of light transmitted through the optical system (as you can see, it's acting as a mirror), but seeing as it's isolated to the centre of the lens then it's not doing any harm at all. Personally, I find them uniquely beautiful - much like each and every snowflake is unique, then so too are these artefacts.

Unfortunately a fix would entail complete removal of the doublet, heating it to soften and separate the two lens elements, and then dissolve the Canada balsam from each of the lenses. A process that that sounds easy, but the critical part is the re-assembly in a clean-room environment with new balsam / optical cement, and requires that both lenses are absolutely perfectly centred - something that requires expertise and the necessary equipment.

Best regards,
Paul

[LLOYDY]

Hi Paul,
Many thanks for posting a comment. The one thing I still do not understand is that I remember the "leaf " effect was complete over 50 years ago when I first saw the binoculars and yet it is now appearing to disappear. I think I have decided to just let it be with the lenses as it would
appear to be a complicated issue to mend. To make matters more difficult the camera/photo repair shops have virtually all closed in these parts of England. I was offered £350 for the glasses when I took them to a person to try and find out more information about the binoculars but that was before I got in touch with the Carl Zeiss company and the rubber eye cup split . I don't know if this was a good price or not but I would like to keep them in the family which is why I was thinking of getting them repaired.
Many thanks for your advice. Very much appreciated. Best Wishes Lloydy

[Mikedenmark]

Materials can change. Glass types are different, so it is possible that the pattern disappears. Temperature expansion of the two glass types, and for the balsam between them, are unlikely to be completely the same. Thus, over time, (in this case 60 years) something like this may develope. And, under different temperatures, disappear again. Very unlikely, but not impossible.
(Or, maybe, it is a result of the differences in lens parts thickness. In that case, any bino might delevop these patterns. If one day is one temperature cycle, then 60 years gives 21900 cycles. Like bending a piece of steel wire. Back and fore, eventually, it will break. No matter how strong it is.)

Main issue is, where the pattern is present, the light passes 2 more glass surfaces, so if detailed measurements are made, you will find a light transmission loss of 2-4% through the pattern. (1-2% for each time the light pass a glass surface.)
For everyday use, it is negligible. Eyes are not good enough to notice.

I have read that when people try to heat up such lenses, in order to disassemble them, it is very difficult to avoid miniscule bits of glass coming off the lens glass surfaces.
After cleaning off the balsam, you end up with deteriorated lenses. Reassembly is likely to produce an inferior result.

If you like them, leave them as they are.

[behblc]

As beh goes it appears to be a decent set, the rubber hinges are always prone to being a tad delicate but on the whole, it looks a good set.
I would be inclined to go with Mike D, I have a U Bootglas 7x50 with some lens separation - it works fine, I don't give it any consideration at all.
the late Dougie Biggart serviced a Ross 10x70 for me - some separation present - his advice was to leave it alone, likewise, it works perfectly.