[stillshot2]

A recently acquired a Spiratone 400mm f6.3 lens for FD mount from my uncle. He took some amazing photos with it in the past, and I was excited to use it one of my Canon FD bodies or even adapt it to a Sony E mount camera. To my dismay, it appears there it fungus, correct me if I am wrong:

Spiratone 400mm f6.3 - stillshot2's Album: Photos - PentaxForums.com

I was able to disassemble the rear element group and I vigorously scrubbed both sides of the glass with hydrogen peroxide on a microfiber cloth, yet the fungus-like pattern remains. I am thinking there are 2 elements glued together in that rear bit, and that the fungus is between them. I don't see any possible way of removing these two elements from their metal casing, it seems they are pressed in there. Is there any hope for this lens? What else could I try?

[Paleo Pete]

I doubt fungus is inside a glued lens, there's no way it can get in. The glue used is Canadian Balsam, which gets fairly hard when it cools. (I had to cement lenses together to learn how to repair binoculars in the military. It's heated, centered and cooled.) To open it up you'd have to have some pretty good equipment (and expensive) to be able to get it centered again. Heating is npo problem, a standard hotplate will do the trick, the glue used to re attach fishing rod tips is the same stuff, but the optical equipment to center it would be a problem. Don't know what that one cost, but the collimator telescope we used in the shop was over $5000 in 1975...Centering scope probably close or more.

More likely scenario is the fungus etched a pattern onto the glass, no cure for that I know of. I had to return a lens a couple of years ago for that reason. Seller didn't note the fungus, I got a refund but had to give up a pretty nice 50mm A series lens too...The fungus secretes various chemicals, which is how bread rises, and the particular types of fungus that invade lenses secrete substances that can etch the surface of glass lenses. Once it's done, I don't think it can be cleaned off. I think I may have a little minor etching on a 50mm but it's on the outside edge and doesn't seem to affect image quality. Good thing, it's a K series 50mm f1.4...Nothing I've tried will take it off.

[jbondo]

That does indeed look like fungus. The pattern is typical. I wonder if the glued elements first suffered separation and then fungus got in after separation. In any case, it might be a bit of work to save this one, and it's possible that the glass got etched which means that even if you get it reglued it's iffy if it will perform well again. Best wishes.

[stillshot2]

Yeah... It seems it probably isn't worth the effort to fix then, so I suppose I will keep an eye out for a donor lens. Thanks everyone

[disord3r]

Owing to knowing little about lens construction, I ask a potentially silly question: is this a situation where another defective lens could be salvaged for a single element? Or are the elements in a given lens selected for their end-to-end compatibility with one another?

[niceshot]

A recently acquired a Spiratone 400mm f6.3 lens for FD mount from my uncle. He took some amazing photos with it in the past, and I was excited to use it one of my Canon FD bodies or even adapt it to a Sony E mount camera. To my dismay, it appears there it fungus, correct me if I am wrong:

Spiratone 400mm f6.3 - stillshot2's Album: Photos - PentaxForums.com

I was able to disassemble the rear element group and I vigorously scrubbed both sides of the glass with hydrogen peroxide on a microfiber cloth, yet the fungus-like pattern remains. I am thinking there are 2 elements glued together in that rear bit, and that the fungus is between them. I don't see any possible way of removing these two elements from their metal casing, it seems they are pressed in there. Is there any hope for this lens? What else could I try?

I had fungus on my lens and I used ammonia and hydrogen peroxide , after I used hot water and dish soap and used latex gloves to rub it clean. After I cleaned it the rest of the way with alcohol . I did the job, but the soap and water and Latex gloves removed the film of scum.

[niceshot]

I think some of the higher end lens makers (Leica) claim to match the elements in the lens, but for 99% of lenses out there, the parts are completely interchangeable from one sample of the same model to another.

Heck, for some, you can even swap elements between brands. The "Tomioka" 55mm f/1.4 lenses are the classic example, with elements swappable among models by Yashica, Chinon, Revue, and Cosina lenses, among others, despite differeces between the mechanical parts of the lens.

Interesting and why not?

[Paleo Pete]

There's also the fact that some companies made lenses that were rebranded for different companies as well, or made to fit different cameras, in which case the bayonet mount would be the only difference. Vivitar for example, had lenses made to their specifications by several different companies. As long as it's the same model, chances are the parts might swap. I swapped lenses in a Vivitar 200mm with TX mount, Tokina made I think, worked fine but still didn't fix the lens...