Fungally challenged lens.

[Mike Kennedy]

I have tried everything from 2 days in the sun to 8 hours under a 60W bulb. Took my S.K.Grimes spanners and opened up the front but the haze is so far into the lens I dare not go further.(Already have 4 paper weights).
Is there a simple "Lens Test" I can perform to see if the glass is a keeper or a bench sitter? Maybe a subject I can photograph to determine the effects of the internal hazing.

Thank You

 

[David H. Bebbington]

Biggest problem with mould (which looks like ice crystals) is - it spreads quite quickly. Even if the mould is not so bad right now as to make the lens unusable, it will be some time soon. Furthermore, mould eats into the glass surface, so the only totally effective cure is stripdown, cleaning, repolishing and recoating, which will be economically viable only if a lens is very valuable and it is totally impossible to obtain another example. Haze due to common or garden dirt is not so terminal but still needs professional stripdown and cleaning.

 

[Mike Kennedy]

Thanks David.Great advice.
The lens was a freebie,ergo, I'll give it a try and shelve the thing if it doesn't perform well.

Mike

 

[Peter Black]

Biggest problem with mould (which looks like ice crystals) is - it spreads quite quickly. Even if the mould is not so bad right now as to make the lens unusable, it will be some time soon. Furthermore, mould eats into the glass surface, so the only totally effective cure is stripdown, cleaning, repolishing and recoating, which will be economically viable only if a lens is very valuable and it is totally impossible to obtain another example. Haze due to common or garden dirt is not so terminal but still needs professional stripdown and cleaning.

Something I have often wondered but never been sure about: will the fungus spread to other lenses if they are stored together in a bag or suchlike? In other words, keep affected lenses well away from good ones?

 

[David A. Goldfarb]

Sometimes, even if there is coating damage, the lens may still not be too bad. I got a Canon FD 400/5.6 once very cheaply (I think it was around $150) in perfect mechanical condition, but with a serious fungus problem. I invested about $80 in a thorough cleaning, but not repolishing and recoating, knowing there was some coating damage. I still use the lens quite often. Maybe there's a slight reduction in contrast, but it's a sharp, functional lens. Find the fungus damage in this shot--

 

[David H. Bebbington]

Something I have often wondered but never been sure about: will the fungus spread to other lenses if they are stored together in a bag or suchlike? In other words, keep affected lenses well away from good ones?

Based on bitter experience, I keep any lens which I am not likely to use for any length of time in a Ziplock bag with a sachet of silica gel. As I understand it, mould spores are present in the air, but putting mouldy and good lenses together can't be a good idea!

 

[Peter Black]

Seems like a wise move David!

 

[Mike Kennedy]

Results.

Looks like my lens cleaning etc. worked out o.k.
Thanks for all the info.
Shot with a Yashica 35-70mm.