Fungus and lenses

[ferny]

It's passed down from person to person, "don't buy a lens that has fungus". But why not? What does it actually mean? Can it be removed easily? If it can, does it harm the lens?
I may be showing my ignorance here. But I've only seen people say not to buy a lens with fungus, I haven't seen anyone say why. I assume it is just more hassle than it is worth to buy a lens with fungus on the cheap and clean it.

 

[malachite]

Well, you have to pay for the lens and then pay to have the fungus removed by a camera tech. Then there's a 50/50 chance that whatever particular type of fungus was in there can etch itself into the lens coating or the glass itself.

In arid climamtes you have lichens that grow on rocks and actually eat it away over time. In humid climates I've seen old not so old cars in junkyards where molds, funus', and whatnot that have eaten the paint right off in a matter of just a few years.

Better to buy something without mold/fungus to better your odds of a working component.

 

[BernieSC]

A lot of times fungus might not affect the lens at all. If there is a small amount you would never see a difference but unless the growth was stopped it could cover the elements and then start affecting the quality. If you can get a good lens at a cheap price that has a small amount of fungus then it would be worth it. If you hold the lens up to a bright light fungus usually looks like tiny spider webs across the elements. But I have seen some form a haze over the inside of the lens.

 

[ferny]

I knew it would effect the photos and thought it would be hard to get rid of. But I didn't know it could damage the glass itself.
Now I know a little more. Thanks for the replies.

 

[ksmattfish]

Some lenses are a lot easier to diassemble than others. I would probably never purchase a lens that I want to use for "serious" photography that has fungus, but I'll pick up vintage cams that have fungus in the lens.

If the fungus isn't in the center of the lens then often stopping down to f/11 or f/16 can keep it from getting in the way. I had an old MF folder that had wispy, hair like fungus around the edges, but I pretty much always used it at f/11 or f/16 due to focusing/DOF considerations, and I didn't notice that the fungus affected the images. I left it sitting in a sunny window with the shutter (it was a between the lens leaf shutter)open on bulb for a few weeks, and now I can't see any trace of the fungus. So exposure to sunlight may be able to eliminate some minor fungus.

 

[rangefinder]

I had a Yashica Mat that got fungus in the taking lens. The fungus was inside so there was no way for me to clean it. I continued to use it for some portraits because the negatives were sharp in the center and the fungus created a vignette around the edges.

Best thing though is to get a lens without any problems. You can always do the vignette later in the darkroom or in photoshop.

 

[Corry]

I didn't know lenses could get fungus. Ya learn something new everyday!

 

[Varthlokkur]

I didn't know lenses could get fungus. Ya learn something new everyday!

Yeah, they are usually the ones that have sat in the back of the closet for years. Just hold the lens up to a loght and look through it. You can see it plain as day.

I would never purchase a lens with mold. Not worth fixing and not worth any loss in sharpness.