Fungus Speed

[David]

I hope this isn't a repeat topic. I searched for some keywords on this and got no hits.

Anyway, I bought a sizable used camera lot. It was $35 with shipping but worked out to $3.18 per camera and lens. It had three pieces I was interested in -- a Honeywell Pentax SP1000, an M42 55mm lens (on the SP1000), and a Sears brand M42 55mm lens with a maximum aperture of 1.4. Each of the three lenses (also a Sears K mount 50mm, feh) have fungus. The f1.4 has it the worst -- threads the full circumference from the edge inward. So I'm going to clean them and remove the fungus. Since the coatings are likely etched anyway, they'll make good practice. However, I'm not likely to have time to do this until later December or early January. So, three questions:

1- How fast does Fungus grow? With the lens caps off and the lenses stored where they can get circulated, dry air, will the fungus grow noticeably or at all?
2- Can the fungus spread to my good lenses?
3- If I stick these things in the freezer to halt the fungus and sublimate any moisture in the lenses, will they survive the freezing or be ruined even more so?

[Excalibur]

[Attila]

http://forum.mflenses.com/storing-lenses-t812.html

[visualopsins]

Fungus goes dormant, hibernates at humidity lower than about 50% -- use fresh/re-charged silica gel or rice baked in low oven thus to remove moisture, to lower humidity inside airtight enclosure, to store.

Acidic (& basic?) fungus metabolites -- the waste from fungii breathing, crapping, pissing & sweating -- can etch coatings and glass. Over time, oxygen turns the acids to mineral salts.

Dormant hibernating fungus may produce stronger acids, but in less quantity, than growing fungus. A fungus recycling from dormant to active many times may produce the most acid, especially upon awakening. If correct, reasons to remove fungus sooner rather than later, even if the fungus is kept dormant until 'later'.

I would make an assessment which ranks lenses by the degree of fungal growth and by the degree of difficulty to work on particular lens, then save the hardest/worst for last. Fifties are so simple and quick to disassemble I'd open that one just to clean the elements to get some idea of how the remaining lenses might clean, whether there is etching, etc..

[peterqd]

I agree with everything said. The fungus will become dormant in unfavourable conditions (light, airy, dry), and new fungus can also only start or spread in favourable conditions.

One thing keeps bugging me though. Is "fungus" the right term? I prefer to call it mildew, or perhaps mould. "Fungus" for me conjures up images of rhizomorphs and smelly fruiting bodies (mushrooms). Maybe the strands are rhizomorphs of a kind, but have you ever seen fruiting bodies on lenses?

[Attila]

Certainly mold is right term, not fungi.

http://en.wikipedia.org/wiki/Mold

[visualopsins]