How to Clean Fungus From a Lens

eBay and the like are veritable treasure troves of interesting old lenses. One of the common issues with these lenses, however, is the presence of fungus. This helpful video makes it easy to clean the inside of the lens and get it working like new!

First, a disclaimer: this involves disassembling your lens. While I wouldn't have any qualms about trying it on a $50 FD lens, I wouldn't dream of doing it on newer glass, particularly since it will void a warranty. 

As you can see in the video, the process involves first removing the front element of the lens with a lens spanner wrench, then carefully removing the offending elements. Next, gently wash it under hot water with dish soap, and press it in a high quality paper towel (to avoid paper lint). Pour some vinegar over it to remove any residue, then use latex gloves to gently place the element back in place and reassemble the lens. 

It's a particularly helpful method for those shooting mirrorless, where the vast availability of adapters and manual focus aids make it a blast to try out the lenses of yesteryear. Do you have any helpful cleaning techniques? Share them in the comments!

[via ISO 1200]

Alex Cooke's picture

Alex Cooke is a Cleveland-based portrait, events, and landscape photographer. He holds an M.S. in Applied Mathematics and a doctorate in Music Composition. He is also an avid equestrian.

Log in or register to post comments

Interesting article, personally, I like to use toothpaste on a cotton bud. The abrasive is just soft enough not to scratch the glass or coatings and the bactericide stops any further growth. The advice to start on cheaper lenses first to gain skill and confidence is solid though!

That's a clever idea; I would have never thought of that! Great tip!!

@Alan. Stopping growth of fungus is a full time thing since there are always spores in the air and on objects ready to start growing. Keeping gear dry and stored in low humidity is the key.

Did that with all my lenses for 4x5. BTW you need three factors for fungus to develop except spores themselves. 1. moisture 2. lock of UV light 3. warm environment. So if you want to store lenses safely, remove one of those factors. The easiest is to remove moisture with silica gel in airtight case. 2nd is to shoot often in daylight ;)

Fungus doesn't need warmth or light to grow, at least not in the way one would think. That is why you often see fungus growth behind walls. Eliminating excess moisture is the key. Keep gear dry and stored below 40% humidity and you'll have no growth. 40% is to have a buffer zone since mold can start growing in as little as 50%.

I meant lack of UV light as the absence. It is a typo in point 2. but I will leave it there. UV light will kill mold. The temperature is a factor though. Lower the temperature, slower the mold will develop.

Doesn't the fungus affect the coatings tho? Granted, it'll be better off, but you'll be without coatings. I've seen lenses with massive fungus going across the surface, also on elements way down in the groups. Not as easy to clean.

Yes, it typically etches the multi-coating. Unless the growth is new when you discover it, it is unlikely that that the lens will go without permanent damage.

Ahhh so helpful and so gross lol.