Slide projector lens fungus worries

September 30, 2012 3:31 PM

I have a working slide projector, Lens A with the proper plastic-only screw-on attachment but with lens fungus, and Lens B without fungus but with no attachment to connect to the projector. Can I do anything to clean the attachment from Lens A and put it on Lens B without worrying about spreading the fungus?

Hi there, AskMeFi!

This is something that has been bothering me for ages. I have a Kodak Ektagraphic III A slide projector. This projector has a little interior white ridged thing that holds lenses in place for focusing. Per internet consensus, it appears that the ideal Kodak-format projector lens for my purposes is the Golden Navitar 70-125 F2.8 (1, 2). This lens originally comes with a plastic-only cylinder screwed into the back of the lens that connects to the white focusing part in the projector. Without the connector, the lens sits loose in the opening and cannot be successfully used or focused.

I've tried a couple of times to buy this lens off of eBay. The first time, I wound up with what I'll call Lens A, which included the screw-on plastic cylinder, but the lens itself had fungus in the front element. I tried to purchase this lens a second time, and this time, which I'll call Lens B, the lens was fully intact with no fungus, but the plastic cylinder part was not included.

Since the screw-on cylinder can be fully separated from the lenses and is just a hollow piece of plastic, is there anything that I can do to treat or clean this plastic cylinder from Lens A, put it on Lens B, and use it in the projector without risking spreading Lens A's fungus to Lens B, the projector, or my slides?

(Also, in any case, just by having Lens A around, do I risk fungus spreading around my house? If so, how do I best dispose of it?)

Thank you, all!

posted by stleric to home & garden (2 answers total)

I would try disassembling unit A, soak it in a bucket of rubbing alcohol (NOT bleach) overnight, then lightly wipe away at the fungus spots with a lens cloth. Scrub the various cylinders inside and out with an appropriately sized bottle brush.

If you can't get the lens clean (or the fungus has actually etched the lens), I would do the same with unit B (minus the need to try to wipe off the lens itself) and then reassemble what you have into one working unit.

FWIW, that sort of fungus doesn't usually pose a health risk, and spreads glacially slow. Kill it when you find it, but otherwise, don't worry too much about it.
posted by pla at 3:45 PM on September 30, 2012

Thank you for the tips, pla! Worth noting, the plastic cylinder itself when removed from Lens A does not seem to visibly have fungus on it -- the photo is perhaps a little misleading, that's just specks of dust that you see on the black plastic. I'm just worried, rightly or wrongly, about the possibility that spores that aren't readily visible to me may have spread from the front element of Lens A to this removable plastic section.
posted by stleric at 4:12 PM on September 30, 2012