spotting lens seperation
I recently sold a lens to someone and they returned it saying that there was lens separation. I don't see it and I'm a bit embarrassed to tell you the truth. I can spot bad separation but not minor separation, I guess. I asked a friend to seek his opinion ind he can't see spot it either but neither of us are "experts". Well it was a clean transaction and clean refund so there is no dispute. I'll keep the lens because it takes nice pictures but I want to know for my own sake and perhaps get a third opinion. This is an old Contax RF 50mm f1.5 Sonnar that I bought from keh.com (if that matters) in brg or ex condition, I don't remember.
So can anyone in the bay area inspect my lens? You can PM me and we can arrange a meeting somewhere if you are willing.
I thought about going to a photography store but I'm not sure if that is appropriate. I feel like it is asking a mechanic to check up on a car for free.
If this is in the wrong forum then can a mod please move this to the appropriate one.
Or they know tooo much. I suppose a bright line at the edge of an element group looked at from the very very side might be construed as such, depends if you are selling it as mint or used. Almost every Duesenburg is technically a "salvage" or "rebuild".
Separation can look like a "soap bubble" at the edge or even center where there is a very slight void in the balsam or cement. Lenses older than 30 years sometimes had a little of this somewhere, or got some after a decade.
Look for "soap bubbles" sometimes people think, and it appears to be a coating blemish. A true coating blem would have less effect on the image formation than separation.
I agree with mr Finley too.
Go into the camera store when they are not busy and, in an interestingly delightful way, 'mention' that you would like his opinion as to whether there is separation. Vinegar catches few bees. Honey does. - David Lyga
I too agree with Henry Finley.
don't we all:munch:
Originally Posted by Mustafa Umut Sarac
Have you tried a small LED torch?
These are excellent for showing up any faults with a lens (although they will make perfectly healthy lenses look horribly dusty). You can find some powered by three AAA batteries here for a few pounds which are an excellent idea if you're going to a camera fair. Rather than holding the lens up to the light you can give the internals a thorough inspection before buying.
I inspect my all my lenses with a small LED torch because every lens look perfect otherwise and i wouldn't dare advertise any lens as mint, even if I think it was. It might be an overparanoid buyer, one with high expectations, or one who backed out. I'm not a frequent seller but I have sold a few lenses and this is the first return so I must be doing most things right. I'll just re-inspect the lens and forget about this incident...
One of the lenses I service (Olympus 75-150 f4 zoom) has a regular problem with element separation. When I look to the center of the lens (where I know the element is) I see what looks like either a hair inside the element or a circle inside the element, like a big bubble. The area inside the circle is still glued together, the area outside has "popped" or is not glued. When this lens is separated, it just will not focus. John