Elmarit M 28mm f2.8 ASPH Separation?

[alair]

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Hello everyone,

I recently bought this lens online and after I received it I noticed what looks like separation on the inner element. After browsing ebay I noticed this on a couple different elmarit asph listings.

Wondering if I should return the lens or if it has any effect on image quality?

Thank you!

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[alair]

bump

[adan]

First, is it separation (de-cementing of glass elements cemented into a group)?

Or are these just air bells getting in between the glass and the blackend metal mount (a.k.a "Schneideritis" when especially "bubbly" in appearance)

Schneideritis: https://www.fredmiranda.com/forum/topic/1484530/

Glass/metal air bells are not that big a deal, since obviously glass backed up by opaque black metal is not part of the image-forming light path. Your second image looks like a bit of that. If they get really bad, the "white bells" might (emphasize "might") reflect some light onto the other glass elements and produce some veiling flare.

And I can't really see anything noteworthy in your first image.

True glass-to-glass separation is usually more obvious, often presenting as rainbow (or occasionally gray) Newton rings in the gap between formerly attached pairs of glass - and often extending well into the light path over quite a large area.

https://www.photo.net/forums/topic/447518-canadian-352-summicron-mseparation/

http://camera-wiki.org/wiki/Lens_separation

It is also possible that the black anti-reflective paint, on both the outer rims of the glass or on the metal mounts that hold them, was imperfectly applied in manufacture.

[Maarten]

Separation sounds unlikely to me as well. The modern UV-curing adhesives behave differently compared to the organic Canada balsam that was still used in the 60-ties. I doubt a modern doublet can be separated without destroying the lens.
I vote for the last suggestion made by @adan

[Danner]

Doesn't look like separation to me.  I've seen a few lenses with separation, including my 100mm f/3.5 Bronica GS-1 lens.  Those all had a faint rainbow-like area(s) spreading from the edge around and toward the center of the lens elements.  Your pictures don't show anything like that.  BTW, my Bronica lens still takes absolutely gorgeous photographs, even though its 'rainbow' area covers more than a third of the rear element.

Edited July 4, 2024 by Danner

[crons]

On 7/4/2024 at 2:05 AM, alair said:

Hello everyone,

I recently bought this lens online and after I received it I noticed what looks like separation on the inner element. After browsing ebay I noticed this on a couple different elmarit asph listings.

Wondering if I should return the lens or if it has any effect on image quality?

Thank you!

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

Personally I would immediately return it. I don't buy a thing from eBay. God only knows what this lens has been through. 

[AndreasG]

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Here is a photo of a typical lens separation of an old Elmarit 2.8/28 VIII, which has a reputation for such damages, the rainbow colors aka Newton's rings as explained above by @adan are clearly visible. Surprisingly, the optical quality of the photos is for my eyes unchanged.

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