Is this lens degumming or lens blistering ?

[kinglang]

Hi all, i just buy two schneider large format lens,but saler not discrible some appearance.
One lens looks like have lens degumming ? Have a circle of reflection.

Second lens looks like lens blistering.

Because i have a ALPA stc body,no camera like technika or sinar p2,or a techno. No way to test the two lens.
Ask everyone what is wrong with this? What is the impact? How much does it cost to repair? Thank you all.


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[pgk]

Looks like 'Schneideritis' to me (do a web sear, there is plenty of information on this) - the edges of the lens elements reflecting light due to the black matting coming off. Unless severe it won't affect performance but can reduce value.

[Dan Fromm]

I agree that the bubbles (second image) are probably Schneideritis and are harmless. Don't agree about the edge (third image). I see Newton's rings, so it is probably separation. Mild, harmless for a while and I'm not sure who recements modern lenses.

OP, what's the lens?

[Dan Fromm]

I agree that the bubbles (second image) are probably Schneideritis and are harmless. Don't agree about the edge (third image). I see Newton's rings, so it is probably separation. If possible, I'd return the lens for a refund.

OP, what's the lens?

[EdSawyer]

agreed, minor separation around the edges. won't affect images much, but will affect value a bit.

[pgk]

I have had a lens with substantial separation. It exhibited several Newton's Rings. The thing is that to do so the elements need to actually separate by a distance which allows light interference. I'm very dubious that this could happen just around a small edge section of a large (and solid) element. Doing so would suggest substantial distortion of the entire element. It also depends on the age of the lens and the adhesive used to cement the elements. Again, modern adhesives tend to fail spectacularly or not at all - its Balsam glued elements which I have found are potentially partially unstuck (the good it is that they can actually be separated and re-cemented although this is a specialist job because it requires accurate re-centering (I had my lens sorted out, but only because I knew someone able to do this in an optical firm). There are aways exceptions though!

[Dan Fromm]

pgk, Rodenstock lenses from the late '50s through the early '70s are notorious for separating. I have a 58/5.6 Grandagon with spectacular separations.

[pgk]

I'm sure that you are correct. Its just that I'm not convinced about the Newton's Rings (I have a Leica M fit Super-Angulon with Schneideritis myself.....).

[kinglang]

Thanks all!It's so disappointed.I will borrow a Actus to test the lens.I had contact schneider,them had stop service for any large format lens.