fungus in camera lenses

I've just purchased a couple of 35mm SLR lenses that are nice but have a slight but visible amount of fungus internally. Does anyone have any experience correcting this problem, or at least halting any further progression of fungal growth? It seems as though there ought to be a way to place an infected lens into a ziploc bag with a fungicidal gas and allow the gas to seep into the lens. Anyone with any thoughts/ideas/experience here is welcome. Thanks!

I have read that some people place the lens in direct sunlight so the fungus is heated up and destroyed that way, you have to be careful with it though. Can't remember where I read it exactly but might have been on the old pr.com forums.

There's good news and there's bad news.

The fungus is actually (most likely) trying to eat the coating on your lenses. The good news is that if they are glass lenses they can be cleaned and or de-fungused. It requires in general a compound high in a methyl component such as Methyl Blue or a Methanol. Isopropyl alcohol will remove the visible fungus, but it doesn't usually kill it.

The bad news, the coating (the anti-reflective, Chromatic Aberration and Color correcction stuff) will eventually be seriously degraded by cleaning alone. The worse news is that sufficient level of cleaning of Polycarbonate lenses will have a real bad effect in that they'll get dingy. They seemingly depend on the coatings more. Most newer (?<10 yrs old) lenses don't seem to be affected by this problem at all.

Your really need a lens/camera tech to disassemble the lenses and clean each component of the lens.

The last piece of good news is that if you shoot black and white, you may not notice the lack of coating or damage as much as with color film.

You may even just have mildew (which if I remember my microbiology) will be stopped by UV and isn't normally seen except in lens that haven't been used for a while (ergo, no UV exposure) but they still need to be thoroughly cleaned.

-CDP

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Originally Posted by drg

You may even just have mildew (which if I remember my microbiology) will be stopped by UV and isn't normally seen except in lens that haven't been used for a while (ergo, no UV exposure) but they still need to be thoroughly cleaned.

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Unfortunately, internal mildew might be unaffected. Most wavelengths of UV see glass as opaque.