Fungus - and how to deal with it on MF lenses?

[hs0zfe]

Hi,

not sure what kind of "nursishment" a fungus gets from glass or coated lenses.

i took my gear to Thailand - maybe the warmer and more humid weather produces such issues?

What about its treatment? How much can i expect for CLA service in Bangkok? Hint: it should be 1/5 the American or European price. Or are affected lenses ripe for the trash bin?


Two buyers of Mamiya lenses complain to me. One is a faker, the other one has not submited any evidence. The faker put something on a brand new and mint looking front lens of a Mamiya 4.0 / 210 mm.96 hours from shipping the lens - this cannot be! I noticed nothing, nada, not an object the size of a corn of sand! [color="#000000"][/color]

The other lens is a 4.5/250 mm for the RB-67 and this buyer claims the fungus affects the last two rear lenses.

Does anyone have an idea how labor extensive a CLA service on such a lens is? And how the lenses are kept inside? I think they used glue in the old days... or some kind of dental cement.

Closing, how do you prevent fungus?

Happy Holidays!

Chris

First photo shows the lens 10 days before. The other photos are from the complaining buyer.

[hs0zfe]

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewIt...e=STRK:MESOX:IT

that white dot seems to be some reflection. I really looked at the front lens from different angles and saw nothing, nada on it.

Will try again to post the buyer's 300 kb photos as these are way too small to be useful here, apologies.

[kitalight]

http://cgi.ebay.de/ws/eBayISAPI.dll?ViewIt...e=STRK:MESOX:IT

that white dot seems to be some reflection. I really looked at the front lens from different angles and saw nothing, nada on it.

Will try again to post the buyer's 300 kb photos as these are way too small to be useful here, apologies.

I have a lens with a bit of fungus and I have to really work to get light to reflect off it so it's visible....though it's clearly visible looking through the lens...
I'm just saying that your photos really need to be super clear to convince Ebay that there wasn't any fungus in the lenses....good luck...

Fungus is everywhere and it grows in humid conditions in which there is no air circulation...an enclosed area with humidity is the breeding ground for fungus...
There seems to be 2 stages of fungus...the small spots that seem isolated from the glass....and the second stage in which fungus becomes attached to the glass and etches a spider-web like design on the glass itself....
I don't know how long it takes for stage 1 to become stage 2...or if, by removing the humidity, you can stop the fungus from growing...I bought my lens with fungus in stage 1 with the hope that it's no longer growing...

[Geoff Wittig]

1) To prevent fungus, pack your gear with a silica pack to absorb moisture. The kind you can reheat in the oven and reuse indefinitely is the way to go.

2) Once you've got fungus inside your lens, you can generally get rid of it, at least in the early stages, with sunlight. Open the aperture as far as possible, and park the lens in bright sunlight, preferrably at noon. Orient the lens so light is shining directly down its optical axis. (Make sure the sunlight isn't being focused by the lens onto anything that will melt; and obviously don't do this with the lens mounted on a camera!) The UV component of sunlight will kill the fungus pretty quickly. This won't undo any etching of the coating or glass caused by the fungus, but it will get rid of the organism.