What’s wrong with this lens?

nhodgkinson · Sep 10, 2015

I just bought this lens but am not sure what’s going on with this element? Is it fungus?

Derrel · Sep 10, 2015

It's difficult to tell much from that photo. I see a small "patch" in the lower left'ish area inside the lens that looks like it might be either de-cementing...or a fungus growth...but it's hard to see much; the front of the lens looks a bit glare-y...I can;t tell if I am seeing internal hazing, or if that's a fine, uniform fungus growth, or if it's just a reflection of the ceiling...

480sparky · Sep 10, 2015

I'm with Darrel on this... there's just not enough detail to tell. What he thinks is de-cementing (or lenses that were cemented together at the factory and are now coming loose) may well be texture on the surface the lens is sitting on.

It may be fungus etching. The fungus is gone, but it ate up some of the coatings on an element.

We'll need more detailed (clearer) shots to be more specific.

nhodgkinson · Sep 10, 2015

Yes I’m sorry, that was a bit useless of me. The light, shapes around the edge that look like chipped paint are inside the lens, in-between the two elements, the ones that all have a mirror image.

Derrel · Sep 11, 2015

If I understand what you mean by the look of "chipped paint", that is what de-cementing looks like. A pretty fair number of lenses have a pair of elements that are cemented together at the factory--literally, two elements that have matching surface shapes, and they are literally glued together with a thin film of cement...sometimes the cement separates, and it does sort of look like paint chips.

nhodgkinson · Sep 11, 2015

Yes you got it, those bits. I know it glairy but the offending objects are quite clear. Is de-cementing a problem, will it get worse? I’m not sure if I should I return the lens, he did say it was in perfect optical condition with no separation, which I’m guessing I the same thing?

nhodgkinson · Sep 11, 2015

Here is a clearer one.

lensproblems2

It’s odd it looks like chips on the edge of the glass reflected down on to the bottom but I’ve checked the outside of the element and it’ll all fine.

nhodgkinson · Sep 11, 2015

And one more

nhodgkinson · Sep 11, 2015

I think I've lost you all to the tyime zones but I found the answer. They are chips, tiny little chips on the paint on the rim of the lens that are so small only the biggest one can be seen by eye, magnified by where they are so they appear huge from the front of the lens..