Bubbles around lens edges on Componon-S and other lenses...?

Good morning all,

Wonder if some of you could fill me in on something I've been noticing with many enlarger lenses for sale these days...

I have seen many Componon-S and some other Schneider and Rodenstock lenses which appear to have bubbles
around the edges of the lens internally, basically where the glass seems to be mounted to the lens barrel.

I'm sure some of you out there have lenses in this condition...do you notice any degradation of quality or performance?

Thanks for your input.

J

What you see might be reflections from the ground sides of the lens elements. Or reflections at seperations of cemented lens elements.
Both kinds of reflections look totally different.

It's known as schneideritis. It has no effects whatsoever on image quality and is where the blackening has come away from the edge of the lens cells.

Ian

Thanks for the education on this-did a search on "schneideritis" and volumes of info came up, much appreciated.

Seems to be cosmetic only.

Ian Grant said:

It's known as schneideritis. It has no effects whatsoever on image quality and is where the blackening has come away from the edge of the lens cells.

Ian

Click to expand...

It's greatly bothersome to individuals who would rather look at their lenses than use them. I've gotten some great buys on older lenses because of this, which as Ian said, has no effect whatsoever on the image quality. L

Theoretically, more stray light would scatter off the inside of the ground lens edges when the paint separated from the edge vs a pristine edge blackening. This would theoretically increase veiling glare and slightly decrease contrast.

However, since no one has noticed a difference I'd say the effect is negligible, amounting to a contrast change of less than ~5% (the accepted threshold of human perception relating to contrast). Stray light off the inside lens edges is probably a weak contributor to begin with.