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alexmuir
22nd August 2019, 10:46 AM
I’ve managed to dismantle an old lens that has been attacked by fungus. What is the best way to clean the affected glass? Will a simple lens cleaner do, or is there a better alternative? The lens is Japanese, from the mid ‘60s, and is coated. It is not of any great value. Thanks.
Alex


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mpirie
22nd August 2019, 11:45 AM
I heard that leaving the lens in bright sunlight can kill the fungus.

For you and me, that would mean sending it somewhere else, judging by the current weather ;)

Another option is a peroxide solution....used in hair bleach.....again, not something i use being almost bald :(

Mike

alexmuir
22nd August 2019, 11:48 AM
Thanks, Mike. I’m sure I’ve heard peroxide mentioned before. I don’t know if the fungus is alive, or dead, but it has to come off before I can use the lens. It’s not worth sending for repair, but it would be nice to clean it if possible.
Alex


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GoodOldNorm
22nd August 2019, 12:31 PM
Try all the usual cleaners first off washing up liquid, alcohol, household bleach or window cleaner. I cleaned fungus off a hasselblad lens with bathroom mould killer spray. It was the rear element I dont think it was coated. Sometimes it is not fungus on the glass or on the coating the marks are actually etched in. These type of marks cannot be removed by cleaning using soaps or mild solvents. I would try a small area of the lens first with a cotton bud soaked in any spray glass cleaner or just use a lens wipe. If the coating is damaged the worse you could do is wipe away the damaged coating and hopefully the marks. There is a good video on youtube showing you how to clean a lens by The Angry Photographer I don't like him but his advise on cleaning a lens is good.

Svend
22nd August 2019, 01:15 PM
Alex,
Some good info here on the Leica forum, esp. post no. 10:

https://www.l-camera-forum.com/topic/111787-lens-fungus/

Looks like you use alcohol to clean it, then sunlight to kill the stuff. For the latter, send it to me -- we haven't had rain since June :)

alexmuir
22nd August 2019, 03:20 PM
Thanks Norm and Svend. I’m going to tackle it this evening. I will start gently to see how it goes.
Alex


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B&W Neil
22nd August 2019, 03:44 PM
I normally use isopropyl alcohol + cotton buds and the usual lens cleaning issues - works for me.

It is also advisable to store lenses in a place of strong sunlight with their lens caps and UV filters removed - difficult! The idea being that UV light kills fungus spores.

Neil.

Svend
22nd August 2019, 04:00 PM
Thanks Norm and Svend. I’m going to tackle it this evening. I will start gently to see how it goes.
Alex


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Alex, I have read that the byproducts of fungus metabolism may permanently etch the glass (presumably an acid at work here). So don't be dissappointed if the lens doesn't fully clear. Hopefully yours will be salvageable.

Good luck!

alexmuir
22nd August 2019, 06:01 PM
Thanks Neil and Svend. I have isopropyl available. Poor storage is the problem with this lens. Entirely my fault, I’m afraid. I wasn’t paying enough attention.
Alex


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Michael
23rd August 2019, 08:05 AM
Don't forget tanning lamps, if you have access to one. Less effective than sunlight in terms of time (cyanotype experience speaking) but still a substitute.

alexmuir
23rd August 2019, 09:56 AM
Thanks Michael. I have one that I bought for Cyanotypes. I will dig it out tonight. I managed to clean the accessible glass quite easily with Isopropyl Alcohol, followed by ROR. The alcohol can leave a light residue on the glass, but removes all trace of the fungus. The annoying thing is that the forward sections of the lens came apart with ease, but the rear wouldn’t budge. I’m in the process of re-assembly, and will see how it performs. The lamp should kill the remaining traces of fungus in the inaccessible area.
Alex


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John King
27th August 2019, 12:49 PM
Thanks Michael. I have one that I bought for Cyanotypes. I will dig it out tonight. I managed to clean the accessible glass quite easily with Isopropyl Alcohol, followed by ROR. The alcohol can leave a light residue on the glass, but removes all trace of the fungus. The annoying thing is that the forward sections of the lens came apart with ease, but the rear wouldn’t budge. I’m in the process of re-assembly, and will see how it performs. The lamp should kill the remaining traces of fungus in the inaccessible area.
Alex

I use isopropyl alcohol for a multitude of things and have yet to see any residue on the glass, or for that matter any surface.

What purity are you using? It seems to be more commonly available as a 95% purity but what I use is guaranteed to be 99.8% pure.

alexmuir
27th August 2019, 12:52 PM
Hi John. It’s 98% if I recall.
Alex


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