Since discovering some fungus on three of my "new" lenses, I have been
thinking about this somewhat.
Maybe it is time to apply a little logic and scientific knowledge to the
problem. I have no idea where this note is headed, but anyway, here goes.
(And as I write this the thought occurs to me that here is a prime research
topic for a Masters or PhD student - and I wonder if any anywhere have
tackled it.)
My relevant background is that I did three years undergraduate study of
botany before doing my Forestry masterate, and fungi were included. I have
also grown grapes at home. Some fungi love grapes. I had to learn a bit more.
Fungi are plants. Plants without chlorophyll. Usually, they need what other
plants need otherwise - a little water, and nutrients (these can sometimes be
somewhat unusual).
What you see when you look with shocked amazement through your
infected lens is semi-transparent tubes (the hyphae, or body, of the fungus),
wandering over the surface of your precious glass. And that's it. The whole
plant. Fungi also usually reproduce my seeds - in their case, minute spores.
I have never seen fruiting bodies or sporophylls on fungus in a lens, though
no doubt it is possible. They might look like a string of tiny beads on a
slightly different style of hyphus.
Fungi have adapted to a wide range of foods; there is one well-known
species that loves jet engine kerosine so much that it can multiply to such a
concentration as to clog the fuel filters.
Fungi have poisons.
String ethyl alcohol is one (eg strong vodka, surgical spirit), and strong
methyl alcohol is another. So are copper salts, boron salts, sulphur dioxide
gas. Vinegar or acetic acid is a very good antiseptic that "never" goes off.
And, apparently, the natural skin oils of humans.
Strong alcohol also dehydrates the fungus and quickly dehydrated fungi
usually die.
So; I reckon that once you have removed the visible hyphae from the surface
of the lens - that should be it. I can't see the logic in swabbing the lens 30
or
40 times more. If you can't see the hyphae, and you have poisoned the
surface with alcohol, then they're probably gone.
But there could be a reservoir of hyphae and/or spores being produced on the
metal surfaces of the lens body - I don't know.
What photographers need to know is what species of fungi are involved, what
they feed on and what poisons them - and what can safely be left behind on
the surfaces to retard their regrowth - and the germination of fresh spores.
I must talk to the local university botany department / microbiology
department.
Cheers, Brian.
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