Prevent further growth of fungus on pentaprism?

I just bought a working Olympus om-2 for about 13 bucks with a pristine 1.4 50mm. Aside from some green spots on the exterior it's in pretty good shape, but there's some fungus beginning to creep up two edges of the penta prism towards the bottom of the viewfinder. Looks like a little forest sticking up! It's very usable right now, but I want to make sure it stays usable for the foreseeable. Is there anything I can do to slow down or stop the growth of this fungus?

If you haven't done so already, get the camera serviced, and in particular, get the foam under the top cover replaced.

4season said:

If you haven't done so already, get the camera serviced, and in particular, get the foam under the top cover replaced.

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All right, it may be a while before I get a chance to send it away. Taking the top off on this particular camera is an expert job due to the sensitivity of the electronics to static, and not every tech does it. And I don't much like some of the famous Olympus techs in America. Some are pompous and seem to be deceitful. So I would allege. I won't name names here.

Is there anything I can do until then? Will exposing the camera with lens off to sunlight or ultraviolet from a black light do anything? It seems like I could get quite a lot of sunlight in there by leaving the camera face up in the windowsill for a about a day at a time with no lens on. Or better yet, I can set up a dust free environment and expose it to my black light, if that kills the fungus.

UV light kills fungus. I don't know if a black light will work or not. There are UV lamps that may be pricey. Sunlight for 6 to 8 hours a day for 2 or 3 days will kill it. Remove the focusing screen before placing it in the UV light.
When working on static sensitive electronics wear 100% cotton clothing, not blends, synthetics, or wool. Wear rubber sole shoes not leather sole shoes. Work on a non static surface such as wood.

RLangham said:

Is there anything I can do until then? Will exposing the camera with lens off to sunlight or ultraviolet from a black light do anything? It seems like I could get quite a lot of sunlight in there by leaving the camera face up in the windowsill for a about a day at a time with no lens on. Or better yet, I can set up a dust free environment and expose it to my black light, if that kills the fungus.

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Ultraviolet light probably won't be of much use, but cool (not cold!) dry storage may preserve it better.

If you have been collecting and using long enough, you come to find that all cameras have some weak points. Some of these weak points can be remedied more easily than others. Pre-EL Nikkormats can get jumpy meter needles. Nikon F2 meter finders can become difficult to service without sending them to Sover Wong. Konica FT-1s can have problems with their electronics. Greg Weber has the parts and the expertise to repair them. Some manual focus cameras which can be repaired and which will good service afterward include Minolta SRTs, Canon F-1/F-1n/New F-1, Canon FTb/FTbN, Pentax Spotmatic/Spotmatic II/2a/F, Pentax KM and K1000. This doesn't mean that other models can't be made to work but cameras which rely too much on electronics, with some exceptions, are more difficult and expensive to keep running.

shutterfinger said:

UV light kills fungus. I don't know if a black light will work or not. There are UV lamps that may be pricey. Sunlight for 6 to 8 hours a day for 2 or 3 days will kill it. Remove the focusing screen before placing it in the UV light.
When working on static sensitive electronics wear 100% cotton clothing, not blends, synthetics, or wool. Wear rubber sole shoes not leather sole shoes. Work on a non static surface such as wood.

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I'm smart enough to know that I'm way too dumb to work on cameras. You see my signature line? It's barely even a joke. Whoever ends up opening it won't be me!

dynachrome said:

If you have been collecting and using long enough, you come to find that all cameras have some weak points. Some of these weak points can be remedied more easily than others. Pre-EL Nikkormats can get jumpy meter needles. Nikon F2 meter finders can become difficult to service without sending them to Sover Wong. Konica FT-1s can have problems with their electronics. Greg Weber has the parts and the expertise to repair them. Some manual focus cameras which can be repaired and which will good service afterward include Minolta SRTs, Canon F-1/F-1n/New F-1, Canon FTb/FTbN, Pentax Spotmatic/Spotmatic II/2a/F, Pentax KM and K1000. This doesn't mean that other models can't be made to work but cameras which rely too much on electronics, with some exceptions, are more difficult and expensive to keep running.

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Yes, I started out with Canon A series cameras. I was told pretty early on that the ones that didn't work, would probably never be fixed. The A series and the Olympus OM series were both early enough in the electronically-controlled era that they are both reputed to be especially vulnerable to static when open and hard to work on even for experienced technicians, due to the primitive IC's.
This was around the same time that the best "small" computers in the world had the first machine-threaded backplanes--you open the back and there's just a mess of fine gold wire forming the main system bus. The advancements in electronics my generation take for granted were not unpredictable at the time, but the miniaturization to manufacture dense integrated circuits did not exist.

I too am hesitant to open a 35mm camera.

shutterfinger said:

I too am hesitant to open a 35mm camera.

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You hit the nail on the head. I can work on the back shutters of speed graphics with no problem! It's the problem of miniaturization...

"There's nothing like that moment when you realize you've destroyed the shutter entirely..."

ROFL. Every man should know his limits. I know mine (can't tell a joke to save my life) and I salute you for knowing yours.

Put it in full sun, out of doors, if low humidity day, and between 10am - 2pm so as much sunlight hits the trouble spots and bounces around inside the prism, turning as needed.

If the fungus is in areas that can be touched, hydrogen peroxide 3% can remove it or isopropyl alcohol will kill it.

No liquids inside the housing, period.

Take unit inside as soon as you're finished with sunlight, H²0² or alcohol, where there is good climate control (no AC), a room temp towel or other clean cloth surface, no hard cold surfaces and let it rest until room temperature, before remounting.

If nothing else, the full sunlight treatment should arrest the spread of the fungus or mold.

IMO.