How do you deal with fungus in a lens

[Robert Ley]

I'm new to lens repair and have some general questions on fungus.

Do you segregate the lenses with fungus, is it easy to infect other lenses with the fungus.

There are quite a few articles on cleaning lenses of fungus so that is not an issue.

I have a UV light box that I use for alt printing, can a place the lens inside the UV box and will the UV light kill the fungus?

If the UV will kill the fungus, should I do that before I open the lens?

Thanks for any "light" you can shed on this topic

 

[ic-racer]

I just wipe it off and put the lens back together. Nothing special. Fungal spores are everywhere, there is nothing you can do about it. Don't let them germinate; avoid dark moist storage.

 

[Sirius Glass]

Putting a lens in direct sunlight, preferably with the sunlight shinning into the lens will help kill or reduce fungus.

 

[Robert Ley]

I have never had a problem with any of my lenses as I am aware of how lenses should be stored in low relative humidity and I have maintained that low humidity in lens storage. Have you had any experience with UV light and fungus?

 

[xkaes]

Try sunlight. Just because I haven't had any luck doesn't mean you won't. Maybe it will kill it, but it won't make it disappear. It will still be there -- even if you take it apart and try to clean it.

The first think to consider is "How bad is the problem?". Oftentimes the fungus is only on the far edge and does not impact the image. If that is the case, try to kill it will lots of sunlight and store it in a dry place away from other lenses.

 

[MattKing]

Putting a lens in direct sunlight, preferably with the sunlight shinning into the lens will help kill or reduce fungus.

If you do this, the UV (in particular) in the light assists with the fungus, but you need to be cautious about heat build up

 

[Andreas Thaler]

Do you segregate the lenses with fungus, is it easy to infect other lenses with the fungus.

That's a well-known horror story from the internet that never ends

Fungus isn't a virus; it doesn't infect.

Dry, cool, and bright conditions keep it away; its spores are everywhere.

 

[Robert Ley]

That's a well-known horror story from the internet that never ends

Fungus isn't a virus; it doesn't infect.

Dry, cool, and bright conditions keep it away; its spores are everywhere.

Thanks for clearing that up for me. I have never had to deal with lens fungus, but I am learning.

 

[RalphLambrecht]

I just wipe it off and put the lens back together. Nothing special. Fungal spores are everywhere, there is nothing you can do about it. Don't let them germinate; avoid dark moist storage.

I fully agree. Putting you lens on a sunny window sill may be enough to kill the fungus. If you can get to the fungus, clean it with hydrogen peroxide (15%) followed by naphtha and/or alcohol(>90%). If your storage environment is too humid, consider a dehumidifier.

 

[campy51]

What do you do if it's etched in the glass?

 

[Andreas Thaler]

I fully agree. Putting you lens on a sunny window sill may be enough to kill the fungus.

You shouldn't rely on this, as glass absorbs some UV light. I also wouldn't leave a lens in the sun for long periods of time, as this can affect the (old) lubrication.

 

[mshchem]

I get rid of stuff like this. My storage conditions are such I've never had a problem. I've been given some old enlarging lenses, I've re-gifted or donated.

All about the dew point (humidity)

 

[BradS]

I live in a warm and dry climate where fungus isn't an issue but in the past, if I happened to acquire a lens with a bit of fungus, I generally just ignored it and carry on. If it is bad, the lens went out with the garbage. Do the community a favor and take that crap out of circulation.

 

[jonny88]

I’d keep any fungusy lens in its own bag or box so spores don’t float onto your other glass. UV light might zap some on the surface, but it won’t reach deep between elements-so you’ll still need to open it up and clean it (a mix of isopropyl alcohol and a little ammonia usually does the trick)

 

[250swb]

A bit of fungus around the edge won't affect the image quality so kill it to stop it's spreading or look into how you keep your lenses because humidity and darkness will do for your other lenses as well. As for putting a lens into quarantine it doesn't work, fungus spores are all around us, we are all breathing them in right now and opening your drawer to take a lens out lets fungus spores in. The very best antidote is to use the lens and let it have plenty of UV exposure.

 

[koraks]

Putting a lens in direct sunlight, preferably with the sunlight shinning into the lens will help kill or reduce fungus.

Not really. The UV might kill some of the fungus, but the main advantageous effect would be the dissipation of moisture that the fungus needs to grow. Put the lens back into a humid environment and the fungus will happily continue to spread.
Also, UV does NOT 'reduce' fungus - it won't remove existing fungal growth. The theory is that it'll kill the fungal growth, but given its resilience, it's unrealistic to expect you'll ever do a complete job at it. You may slow it down temporarily.

Mechanical & chemical removal is the only real way to deal with fungus, combined with storing the lenses in low-humidity environments to prevent the problem. Note that over time, fungus etches the glass and the coatings, so in bad cases, after removing the fungus itself there will still be permanent and irreparable damage to the glass.

 

[Andreas Thaler]

Mechanical & chemical removal is the only real way to deal with fungus, combined with storing the lenses in low-humidity environments to prevent the problem. Note that over time, fungus etches the glass and the coatings, so in bad cases, after removing the fungus itself there will still be permanent and irreparable damage to the glass.

That's why I wouldn't delay removing fungus until it's caused any damage.

However, a single small fungus star that may have been sitting there starving to death for decades wouldn't be a reason for me to risk opening the lens.