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Steve Sheppard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 06, 2006 - 01:26 am: | 
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I've made a start on working my way through my impressively large collection of fungus infested lenses. Naturally I am removing all the glass elements from their mounts for treatment, and up to now, I have also stripped the diaphragm and washed the components in solvent.
Cleaning the diaphragm is a major part of the job, and I am wondering if it is actually necessary (or effective), or whether it is sufficient just to clean the fungus from the glass, and the metalwork in its immediate vicinity. |
rick
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 06, 2006 - 12:45 pm: |
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I don't know if I've ever cleaned out a lens that looked like it was about to grow trees, but I've generally assumed that I wasn't going to get all of the fungus out of the metal work in any case so I've just cleaned the glass. This always came with an admonishment to keep a very close eye on the lens for any sign of a recurrence, so that it could be cleaned again before it could do damage.
Once you have the glass out, it would be good to set the open barrel in an airy, sunny, dry place for some time. Sunshine (UV light) and fresh air are what fungus likes least. As for a definition of "some time", the more the better.... a week at least. |
Steve Sheppard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 06, 2006 - 02:56 pm: |
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I think you're right, Rick. Certainly if the fungus has produced spores, then the diaphragm, and the whole lens barrel, must be full of them, and it would be next to impossible to completely eliminate them. The best bet must be to make sure the lens is never kept in conditions where the fungus can get started again.
Probably catching the problem early enough can improve the odds. Assuming that "our" fungus behaves like other fungi, the familiar fine threads are presumably the myceliae, which do not produce spores. To generate spores, fungi create a "fruiting body". Does anyone know what this would look like in lens fungus? A couple of the lenses I have stripped have had, as well as the threads, irregularly shaped flat areas of fungus, with what looks like a tiny lump in the middle. Could these be the fruiting body?
I'm afraid here in the UK the sunlight treatment is a non-starter for at least 9 months of the year! I have bought a little UV-C sterilizing lamp which I wave around over the lens components, but whether it has any effect I don't know! |
Doug Wilson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, May 06, 2006 - 05:43 pm: |
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Hmmm...
...I wonder what very low temperatures would do to our little "furry" friends? |
rick
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 07, 2006 - 08:47 am: |
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I've seen one Miranda in which the fungus looked like little trees, reaching up maybe .02 or .03 inches from the surface. Pretty cool looking, as long as it's not MY camera.
I don't think cold temperatures would kill them - they'd probably just sort of hibernate until it warmed up..... |
Steve Sheppard
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 07, 2006 - 01:57 pm: |
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Just had visions of a bunch of cryogenically preserved lens-eating fungi waking up after the human race is extinguished by an asteroid, and taking over the planet!
It might be interesting to know if the fungus we are dealing with is just some sort of everyday general-purpose fungus, or a more specialised organism. What did it live on before there were tasty coated lenses for it to chew? |
Doug Wilson
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, May 07, 2006 - 07:38 pm: |
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Just did the Google thing and Rick, once again, is correct. Although, it will stop it from spreading until you find a way to eradicate the stuff.
Stanford University's site discusses some options for removing fungus from books in libraries and Thymol was on the top of the list:
Thymol (isopropyl-meta-cresol) is a phenol. It is in crystalline form at room temperature, and sublimes to vapor when heated above 120° Fahrenheit.
Thymol is toxic, and can be absorbed through the skin, by inhalation, or by inadvertent ingestion. The major hazard to those using thymol for fumigation is inhalation. Thymol has a pungent odor, however, which serves as a good warning to those working with it. Symptoms of overexposure include gastric pain, nausea, vomiting, and central nervous system overactivity. Very high levels of exposure could result in convulsions, coma, and cardiac or respiratory arrest. Long term effects from repeated exposure include liver and kidney damage, and dermatitis.
If not for the fact that it will give you acne, I would probably take the risk of using it... |
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