View Full Version : Mirror lens fungus

30th December 2009, 08:26 PM
Just took delivery off E-bay a 300mm mirror lens. Only a cheap one at 40. Despite the seller claiming it was mint there are a couple of patches of fungus, not very big at a couple of mm. I have not had chance to take any test pics yet, waiting 'till the daytime.
I know fungus can effect old lens (I have no experience of it) but will it show up in my pictures? or is one of those faults that don't show, like a small scratch on the lens. I assume it will carry on growing, will it cause problems in the future?
Any advice welcome before I leave +feedback or see about returning it "not as described"

Turbo Weasel
30th December 2009, 08:42 PM
I have no experience of fungus. I did read somewhere that fungus could be transferred to other lenses if stored together. I don't know if this is true. Perhaps someone more knowledgeable could enlighten us.

Jim Ford
30th December 2009, 10:39 PM
This is an interesting article on lens fungus and how to treat it:



31st December 2009, 12:06 AM
Thanks for the link Jim, just been reading it before I saw your post.
At the price it's not worth repairing so I'm debating trying to get my money back but then again if the pictures I get from it are O.K and it stays as it is for a few years it's a nice little lens in otherwise excellent condition.
A 600mm (in 35mm terms) that will fit in your pocket:)
I need to try it out properly first I think.

31st December 2009, 04:06 PM
The article Jim recommends is one of the best I've seen on the subject and is very balanced.

You may well find that any optical effects only show up in some lighting conditions. I have an OM 85mm f2 that I was unable to sell to a dealer because of a minor dose of fungus, but I've yet to see any discernable effects in images. Nevertheless, I left it in the sun for a few weeks to kill the fungus & spores just in case...

My personal preference would be for returning the lens to the seller on principle. I had a similar experience last year with a 40mm Hexanon described as "Mint". I suppose the seller couldn't see the fungus for the dirt. Anyway, it went straight back. *yes