Cleaning fungus off of a lense

Jordan Brade · April 4, 2005

I recently purchased a Carl Zeiss 10-100mm T3 zoom lens from ebay a couple days ago, and the lens has fungus on the edge of one of the internal elements. Is there a way I can clean it off myself? Should I take it to a place that specially deals with lens repair? Or is the cost to do it not justifiable, as in I just shouldn't zoom in all the way? Thank you for any help you can give me.

Dan Salzmann · April 4, 2005

Do yourself and the lens a favour and bring it to a qualified lens technician.

John Mastrogiacomo · April 4, 2005

Do yourself and the lens a favour and bring it to a qualified lens technician.

<{POST_SNAPBACK}>

Some places will not touch those kind of lenses, because the fungus can spread when you open the lens up. Better check before you send it to anyone. :(

Max Jacoby · April 4, 2005

With some kind of fungi there is not much you can do, even if you remove it, it will reappear.

April 4, 2005

Fungus and mold tend to love dark damp spaces. It would not hurt to expose your lens to some sunlight. You may be able to stop or slow the growth the fungus by giving it something it hates, sunlight. These older lenses are often left in a case in someone's cellar for years at a time. Dark, damp...not good, unless you are a fungus. When I buy an older lens I clean it and leave it on a table or shelf that gets a good amount of sun.

John Sprung · April 4, 2005

the lens has fungus on the edge of one of the internal elements.
<{POST_SNAPBACK}>

Have you shot tests with it? Test with the aperture wide open and run the whole range of the zoom. Test focused at infinity and fairly close. If the pictures look OK, perhaps you don't need to do anything but just keep the lens in dry air. Fungus needs moisture to grow, keeping the humidity low will stop it. If it's a real problem, tell us where you are and perhaps somebody here can recommend a shop to clean and align your lens.

-- J.S.

John Pytlak RIP · April 4, 2005

Are you really sure it is fungus? Mold and fungus usually need something organic to "eat". Don't know if that lens used cemented elements, but sometimes Canada Balsam or other lens element cements can deteriorate and craze with age or heat.

I agree with the others that having a lens technician evaluate the situation is best for anything that is internal to the lens. If you can't afford that, run appropriate lens tests to see if the lens is okay in its present state, and keep the lens in a stable dry and cool environment.

Dominic Case · April 5, 2005

Don't know if that lens used cemented elements, but sometimes Canada Balsam or other lens element cements can deteriorate and craze with age or heat.

I was told that Canada Balsam is an excellent source of nutrition for fungus, which is why it does sometimes grow inside apparently sealed lenses. I had a less expensive zoom lens dismantled (professionally) and the fungus cleaned off a few years ago: now the fungus is back. So obviously it needs to be killed as part of the cleaning. Maybe a good dose of UV would prevent further growth.

I certainly wouldn't attempt to dismantle a good lens like a Zeiss myself. And after my experience I would want to know more about what a technician was going to do for a permanant cure.

Tom Ballard · April 5, 2005

I was told that Canada Balsam is an excellent source of nutrition for fungus, which is why it does sometimes grow inside apparently sealed lenses. I had a less expensive zoom lens dismantled (professionally) and the fungus cleaned off a few years ago: now the fungus is back. So obviously it needs to be killed as part of the cleaning. Maybe a good dose of UV would prevent further growth.

I certainly wouldn't attempt to dismantle a good lens like a Zeiss myself. And after my experience I would want to know more about what a technician was going to do for a permanant cure.

<{POST_SNAPBACK}>

Removed from the environment they need in which to survive (cool and damp), many fungi will die. This could still leave a blemish on the lens, which may or may not show up on film, depending upon the density and distance from the film plane.

I agree with keeping the lens in a dry area exposed to lots of sunlight, as well as leaving the cleaning to a professional.

Good luck.

Tom

Jordan Brade · April 7, 2005

I have not recieved the lens yet. It was shipped out just recently, so I based my question on the seller's description. He says that there is a little bit of fungus at the edge of one of the internal elements. I won't know for sure how much or how little if it actually is fungus until I recieve it in the mail.

I live in Phoenix, Arizona so even if the fungus can't be taken off, there's a lot of sunlight and very little humidity (if any!) which would mean the fungus wouldn't have much hope of living.

I already called one place near me called Tempe Camera, and unfortunately they said "You can't clean fungus."

However, I think what they really meant was "We won't clean fungus."

If you guys can point me in the right direction to a place that will, any help will be greatly appreciated!

andrewbuchanan · April 7, 2005

Dominic,

Good thought on the UV. I've often wondered if this might be a way to keep lenses clean. They use it to sterilize medical tools, drinking water, bio-hazard areas - why not lenses? I wonder what would a be a good source for a low temp with lots of UV, just a flourescent blacklight? I don't have any lenses with fungus, but if I could "bake" mine with UV everytime I used them in the rain or damp conditions, I would definitely do so.

Jordan,

I have disassembled several zooms and primes myself, and it is possible. However, I would cation against it unless you have the right tools and a good understanding of how the lenses are built. That being said, there is a great deal of info about lenses on Google.

Watch out for heat when you expose the lens to light! If it gets too warm - and particularly if you stand it up to face the sun, grease from the barrel can get hot and run down on to you iris blades or ... the horror ... a glass element.

This is why I really like the idea of a cool UV light.

Dominic Case · April 7, 2005

This is why I really like the idea of a cool UV light.

But on second thoughts, I'm not sure what wavelength of UV is the most effective at killing things. Quite possibly it is short enough to NOT go through glass. So just parking the lens in the sun or under a UV source of some sort wouldn't do much good. (And even if you do kill the fungus you still have to get rid of the bodies. However, a good lens repairer ought to zap each element of the lens while (s)he has it apart for cleaning.

I simply took my lens to the local specialist camera shop. It was a while ago. I guess there could have been two responses: either "it can't be done" - read "we don't want to do it" or "yes no trouble" - read "we'll take your money but no guarantee that the cleaning will last longer than it takes to cash the cheque".

Lav Bodnaruk · January 19, 2006

What about X-raying the lens? Does that kill fungus? I presume even if it did it would still need to be cleaned of the "bodies" but I was wondering what your thoughts might be on this so to best prevent further growth;

i got 10-100 zeiss T3.3 in the blimp housing and i think i got some fungus creeping in... don't knwo for sure as i have never really seen fungus before... its rather tiny on the very edges of the inside elements - kind of looks like spiderweb, very small and thin spider web; thought that maybe i should x-ray the lens, in case it is fungus n not just dust... i maybe able to use dentist x-ray machines;

any thoughts or comments would be appreciated!

ps. none of it appears on the film, the image is clear and crisp, good contrast.

Robert Glenn · January 19, 2006

I think the best thing you can do is to #1 put it in an environment that's very dry --~50% or less relative humidity should be good. Also keep it in a temperature 70 or below. If the fungus ins't too bad then you can probably live with it I heard it's also good to put a lens in direct sunlight for a good 15 minutes per side with the apeture wide open. That should keep the fungus from spreading any more..

Joe Gioielli · January 19, 2006

You can get a uv light at a better pet stope in your area. They are used to setralize [sp] water. You would have to modify it (they are generally sealed units) and they are aren't cheap. To me, it seems like a lot of bother for something that may not work, but it's something to consider.

Best of luck

Joe

Lav Bodnaruk · January 20, 2006

Thanks guys!

Ive actualy got that question of killing fungus with dentist X-ray machines brought up here too

http://www.cinematography.com/forum2004/in...?showtopic=8608

to which John replied with a document that suggests it might leave some yellowing on the lens... that got me real worried as i was ready to Xray it!

The following is from Cine Techic web site and i had pasted in the above thread as well:

"In a worst case scenario, exposure to a strong emission of X-rays can kill fungus. This can be accomplished by exposing the lenses to the output of an X-ray device, set to a high exposure." Cine Technic web site

I guess I am wondering if anyone tried the X-ray thing...

No doubt, as soon as it gets sunny i will take the lens outside (that shouldnt be a problem here in Oz, although we got some weird rain forest like storms right now) and Ill try to see what exposure to UV does... again it may not even be fungus i am looking at, as its tiny, but i just wanted to ask and know my options if it is and it decides to spread...

again, thanks!

rob spence · January 20, 2006

Hi,

I've been told that x rays can kill fungus...not sure how you would go about doing this .

Rob

Lav Bodnaruk · January 20, 2006

Hi,
I've been told that x rays can kill fungus...not sure how you would go about doing this .

Rob

yeah, cool... id really like to try and find out what kind of xrays, what level of exposure.... would the dentists equipment be strong enough? oddly enough i can not goggle anything on this subject..