Very interesting article on fungus entering lenses. I wonder if moisture
plays an important role in the development of fungus.
In other words if you remove the moisture or humidity can fungus still form
in side the lens?
Also , if you've ever seen a fish tank that is being used and has water in
it. On an old tank you can actually see where algae and other things begin
to grow and build up near the top of the glass near the surface. If left
without cleaning periodically the glass can become etched or discolored.
Also take into account of just regular glass on a window pane or indoors on
a cabinet. Does the glass actually look as good as new when cleaned or as
good as the day it was put in.
Also the multi-coatings that are put into the lens surface artificially ,
is this a bacterial growth?
I heard a story and you know how hearsay goes. So here it goes , "on how
the discovering of multi-coating of lenses was discovered" , That the old
German Binoculars were far superior to anyone else's and the reason why was
for the aging of the glass.
Now I am not a scientist and perhaps John could help , but does glass age?
and if it does , does it get better with age or worse?
Great Site and I love hearing the different input and views on things.
Sam ...
-----Original Message-----
From: PCACala@xxxxxxx <PCACala@xxxxxxx>
To: olympus@xxxxxxxxxxxxxxx <olympus@xxxxxxxxxxxxxxx>
Date: Wednesday, October 06, 1999 6:20 PM
Subject: [OM] The last word on fungus
>Here is a recent posting from the Canon FD listserver that ought to give
the
>last word in lenses and fungus. I've never seen such a comprehensive write
>up on the problem:
>***************
>From: snaver@xxxxxxxx (Dr. Richard H. Evans)
>Posted on: canon-fd@xxxxxxxx
>
>Years ago I put my talents as a veterinary pathologist to work when I
>noted fungi on the lens of my old Canon Ftb and Nikon microscope lens
>after they were stored for 2 years. I went hog wild and looked at other
>lens I had and used often and new ones friends had just bought. I found
>out the ALL lens even brand new ones come with fungal spores floating
>around in them. Now - given increased humidity and darkness they can
>sporulate and grow hyphae (called vegetative forms as the grow and
>produce kids) along the glass, producing millions of spores which
>themselves sporulate if the conditions continue and result in those
>beautiful tints.
>
>
>Further, the older the lens, the easier it was to flunk the pressure
>smoke test indicating the lens compartments were not sealed (smoke would
>enter the interior of the lens when passed over the lens under
>pressure), allowing air in with all the bugs it carries. Many of the
>lens I used came from a camera store in Northridge, CA after the
>earthquake. Several of the brand new ones developed colonization by
>fungi released from the earth during the quake. This makes me wonder
>just how tightly the are sealed.
>
>Last year at the request of a friend who owns a camera store, I cultured
>the front glass of 20 used lens and 20 brand new, never out of box lens.
>All 20 used lens had on average 6 species of fungi, while the new lens
>average 1-3 species, until left out of the box for 24 hours, then they
>ranked as high as the used lens. I am not going to tell you the number
>of fungal species on the hand of my friend, he is still in shock today,
>claims "he fells dirty all the time" since I entered his shop.
>
>As a remedy, I tested desiccant packs and found most CONTAIN fungal
>spores and actually very poor moisture 'suckers' as Klaus remarked.
>
>I tried a myriad of antifungal agents. Alcohols such as ethanol were out
>because as Bill says the require soaking which does a job on internal
>portions of the lens and they do not kill many saprophytic fungi.
>Hydrogen peroxide is usually thought of as a sporocidal agent, but it
>ain't necessarily so. Many species spores are not effected by it. Except
>for UV, almost all other commercial agents require the item be immersed
>in it. However, the organic aldehyde disinfectants (actually sterilants
>- such as those used to sterilized medical instruments that can not be
>autoclaved) were the choice as their vapors in sufficient concentration
>kill fungal spores not to mention everything else. The two most common
>are formaldehyde and gluteraldahyde.
>
>I built a airtight box and placed lens in it on a rack with a small dish
>of gluteraldahyde in the bottom and put the whole affair out in sun for
>3-4 hours to get temp up. The gluteraldahyde vapors did the trick. End
>results were that when then the old lens was disassembled in a sterile
>environment, it was sterile. I tried this procedure with 6 other used
>lens and the effect was the same except 3 of them developed weird
>dicolorations and 2 actually fell apart. The gas probably acted as a
>solvent, dislodging all manner of important things.
>
>Radiation - sounds great, but it is dose dependent in it's killing
>effect on fungal spores. Remember, the deserts of California contain
>many species of very, very, very old fungal spores, despite all the
>solar radiation.
>
>Moral of this story - fungi are on and in everything. Good hygiene for
>your camera and lens should keep them from taking over!! What is good
>hygiene you say? Well, I got a used and broken 30 gallon aquarium (free
>from pet store), used a butyl caulk to seal the broken glass, placed a
>small dehumidifier ($10) in it and a all spectrum aquarium fluorescent
>light on top (called a Vitalight in the aquarium trade). I turn it on
>for about 2 hours each week and have not had anymore problems in over 5
>years.
>**********
>Gary Reese
>Las Vegas, NV
>
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