Fungus! Stopping it in its tracks?

Hi all,

 

I've just got a quick question: I've recently been going through all my

photography gear and starting to get right back into it. I've got mostly older

gear and noticed that one of my favourite mini-zoom's (Pentax-m 35-70 2.8) has

started a small mushroom farm! It's not THAT bad, it doesn't seem to noticably

affect the images (shot a few pics on 2.8 down to 5.6, other than DOF I noticed

no difference in sharpness, other than the slight softness you'd expect when

wide open). I did have an old 85mm lens I picked up on the cheap once that was

so infected, just looking through it to focus it had dropped about two stops.

 

I'm just wondering, once a bit of fungus has started, is it possible to stop it

from spreading by filling my camera bag with those little moisture eating

sachet's? Or once the first sign appears, is it simply too late? Also...

(sorry if this sounds completely rediculous!) is there any chance that this lens

can 'infect' others? I just know that fungus spores are good at getting into

the tightest of spaces, so could the fungus spread by keeping this lens in the

same bag as my others (I'd if my 50mm 1.4 got sick!).

 

 

Thanks for your opinions everyone.

Sunlight can kill fungus, but it won't remove the carcass, nor will it do anything for the damage done by the acids that the fungus excretes. Most recommend putting the infected lens in a windowsill for a few days and letting the light into it.

 

I don't know if the lens can infect others, but common wisdom says it can, and it makes sense, so I'd be leery of having the lens anywhere near your good glass.

 

Lenses can always be disassembled and cleaned but I've never done a zoom lens and would not want to try - still there are places that will. If the fungus hasn't damaged the lens coatings, you may be ok, or you have have to live with some damage.

 

If in the final analysis you can live with the small damage done to the lens, then I'd say use it (once disinfected of course). Some can't deal with any lens that is not pristine, so YMMV.

If the fungus is on the outer surface it can be removed. First try a solution of 50% ammonia with 50% hydrogen peroxide. In most cases this will do the job. Some cases may require cold creme. I only recommend it as a last resort as it is a very messy business and difficult to remove. Take note that if the fungus has been allowed to remain on the glass for some years it may have etched the glass, in which case the damage is permanent. If the fungus is on the inside element you are out of luck. I don't recommend disassembling a zoom lens as it is highly unlikely you will get it back together.

Hi guys,

 

Yes, I wouldn't try to dissasemble a lens I actually like! Thanks for the tip Wigwam, I'll try popping in the window sill and see if I notice any change in the structure etc. You said "then I'd say use it (once disinfected of course)", by disinfected, are you refering to killing with a good dose of healthy sinshine?

 

Oh, and thanks for the tip on the ammonia/peroxide Dave, unfortunately it's on an inner element, so I won't be giving that a try in a hurry.

 

Thanks again.

Steve, yes, I meant once you murder the happy little fungi with good old UV radiation from the sun, you can use the lens. Hard to know if the damage done is going to impact your images or not until you try it.

 

I've done some minor disassembly of prime lenses, but have not had much luck with zooms. Oh, I can get 'em apart ok....

"Oh, I can get 'em apart ok...."

 

Yes... me too! I've recently developed a coupele films from different bodies where I used that lens for a few shots and all seems to be good, like I said, at this stage it isn't too bad at all. You have got me thinking though... I've still got an old geological black light, that'd give anything a healthy (or not) dose of UV. Might give that a try I think...

May I ask how does fungus get into a lens? What do you need to do to keep from getting this in your lens?

"What do you need to do to keep from getting this in your lens?"

 

I've heard of people keeping a few packets of those moisture eating granuals in their camera bags all the time, just to stop any moisture forming in the first place. It makes sense to me, no moisture, no mushroom food.

Fungus in a lens is just like any other kind of fungus. The spores are airborne, and they get into everything - lenses are no exception. They need reasonably dark, moist, environments to grow. Like where you would find mushrooms or mildew, like that.

 

So sunny and dry is a good way of keeping fungus at bay. Spores that cannot find purchase will do no harm to your lenses. In addition, I believe that most modern lenses are less likely to be attacked by fungus - the main culprit in times past was the 'Canada Balsam' that was used as a cement between dissimilar glass in lens elements. I suspect that type of cement is no longer used in modern lens production. Apparently, fungus loved to nibble on that stuff...