Can I use UV light to antifungal for lenses ?

check_box · Joined: 02 Jan 2014 Posts: 18

I have some old vintage lenses of CZ and Leica, I want to antifungal for them. I think sunlight exposure will harmful for them because temperature of the sun.

And, I think I will use UV light to antifungal with no temperature effect. Is this method works ? And which UV lights do I must choose ?

ForenSeil · Joined: 15 Apr 2011 Posts: 2726 Location: Kiel, Germany.

Do you already have fungus grown inside the lenses or is it preventive?

You theoretically could kill (but not remove) fungus with an UV light from UV bulbs, though it's generally inefficient and it might start growing again very fast from areas which the light didn't reach when moisture is high enough again.
Glas inside the lenses is blocking most UV light, so light source has to be very strong.

I guess your light is a 4W blacklight (380-420nm) bulp. That would be very ineffective I guess, not even good enough for superficial cleaning. There are similar ones with stronger UV light (254nm etc.), though they they generally also only have not enough power to be efficient through thick glass.

In some hardware stores very strong UV-A bulbs can be bought for pool water sterilsiation pumps etc., though their light cancerogenic etc. and should be only handled with a lot care, and depending on thickness and transmission if the glas it might take some hours aswell.

For only killing the fungus I would prefer a cheap chinese ozone generator (at least 2-3g/h, around 15-30$) in a box with the lens for some days instead, easier to handle, can also reach and sterilise dark places inside the lens.

Or direct sunlight, cheap and works several times faster than a 4W blacklight for sure. A little heat like 45-50°C can be also easily tollerated by most lenses, but not by most funghi (same with temperatures colder than -20°C).

be careful not to start a fire Wink

Though all these methods don't remove the fungus, they are only killing it.
Also a dead fungus is a good substrate for another one, it's only buying some time if it's useful at all Wink

Best way for an infected lens is to remove optical elements and use aqueous alcoholic solution (~70% rubber alcohol/isopropylacohol or ~70% ethanol) and a soft towel to remove the fungus, that kills both spores and mycelia and removes dirt and dust and is gentle for residual coatings.
Though it needs some DIY skills or a professional repairman^^

bernhardas · Expire: 2017-05-23

edited

Gerald · Joined: 25 Mar 2014 Posts: 1196 Location: Brazil

The glasses used in photographic lenses block UV. Sad

The fungus inside the lens will smile when you turn on the UV light. Mr. Green