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Elmarit 21mm pre Asph question


ibramr

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Greetings.

 

I have acquired this lens very recently. I am still going through the familiarization process with it on M9. Albeit used, it is in a very good physical condition. The only concern I have is what appears to be to me as some crystallization of possibly the adhesive material around the outer periphery of some of the lens elements. It is noteworthy, that this crystallization (if this is the correct name for it) has no impact on results. A picture is attached for your use.

 

I would appreciate your opinion if this is a normal phenomenon for a lens of that age, it is really the crystalization of the adhesive material (and not fungus for instance), and what is the likely impact as time progresses.

 

Thank you very much.

Elmarit21mm.pdf

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Mine doesn't exhibit that, but I have seen it before on other lenses. It is not the cement between elements, or any kind of adhesive. It's some flaking of the dead-black paint around the side of the element(s). It just looks like it's facing forward, it's an optical illusion. Theoretically a few stray rays of light could get misdirected as a result, but in practice I defy anyone to demonstrate any noticeable effect as against a "perfect" sample of the same lens. However if it disturbs you and you can still return the lens, these are far from rare and plenty of umblemished samples are out there. It's a fine lens btw, I bought and sold an ASPH and kept the pre-ASPH. Mine is the later version with the pushbutton shade (the earlier ones had pins and a push-and-twist shade.

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Mine doesn't exhibit that, ....... I bought and sold an ASPH and kept the pre-ASPH. Mine is the later version with the pushbutton shade (the earlier ones had pins and a push-and-twist shade.

 

Thank you Bocaburger for your advice. So far, there is no effect on the lens' results. I acquired this lens at a very reasonable price inclusive of its finder and its pushbutton shade. I have the intention to send it to Leica for coding some time in the future, and may then ask for a complete service. So far the results are very nice on the M9 albeit there is a minor vinigtting, mainly on the lower right side, that I expect to disappear as I step the lens down. Once more, thank you very much.

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Actually, this is not "flaking of paint" - since the paint or black coating is trapped between layers of glass and metal, and thus not subject to any force that would cause it to flake.

 

It is a minor separation of the glass from the black-coated metal underneath, which allows air infiltration. The difference in refractive index between the air and glass causes the white appearance, just like air bubbles in/under/behind ice.

 

http://www.alaska-in-pictures.com/data/media/6/frozen-ice-bubbles_2362.jpg

 

Usually, the separation is on a forward-facing "ledge" in the lens barrel that helps support and mount the lens element, and thus is out of the light path, and thus will have little or no effect on image quality.

 

It is most common with wide-angles of a certain age, since their bell or funnel-shaped designs have lots of stair-steps as the lens barrel narrows in size from the large front element to the point where the aperture is placed. Fairly common with the Minolta CLE 28mm:

http://i.ebayimg.com/t/MINOLTA-CLE-OBJEKTIV-M-ROKKOR-28mm-1-2-8-LEICA-M-MOUNT-R14-/00/s/MTA4MFgxNjAw/z/FUQAAMXQqExRmgCE/$(KGrHqIOKosFGVQF4PUgBRmgCEJCVg~~60_35.JPG

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Actually, this is not "flaking of paint" - since the paint or black coating is trapped between layers of glass and metal, and thus not subject to any force that would cause it to flake.......

....

It is a minor separation of the glass from the black-coated metal underneath, which allows air infiltration. The difference in refractive index between the air and glass causes the white appearance, just like air bubbles in/under/behind ice.[/url]

 

Thank you Adan. And so far, there is no impact on the results. Do you think cleaning the lens in Leica NJ would remove this separation? Appreciate your advice. Regards.

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It is not separation. ........something else

 

Tobey,

 

A very good advice, and a request for a quote to NJ was sent 45 minutes ago (with a picture attached). A reply came 30 minutes later suggesting sending it for both 6-bit coding and cleaning. The possible cost of the service and its current price would still be very reasonable for a pre-Asph lens. Once more, thank you.

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  • 3 weeks later...

The lens was sent to NJ two weeks or so ago for 6-bit coding and a clean up.  A reply came today indicating that the lens will be sent to Germany for up to  3 months.  No cost indication till now.  More to follow.  Regards.

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