i think this is a fungal problem

ford1

ford1

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kevin
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guys i got a sigma 500mm lens and when you look down to the inner lens it has two types of growth on the lens its self..the first lot looks like a clear pollen ..just like clear spots all over and the second type is like a bunch of small brown twigs ..now i read somewhere that uv light can get rid of this but has it by the sounds gone to far
..i can get pictures i think


kev
 
sounds like the dreaded fungus, keep them well away from your other gear. You can probably still use it but will probably show up with small apertures:(
 
so is there anyway of getting rid of it apart from a complete strip down that i wouldnt have a clue where to start lol

kev
 
b****r ..i wouldnt know where to start ..ive taken the adapter off and the rest of the screws are in there solid ...dont think thats going to happen lol
 
ford1 said:
b****r ..i wouldnt know where to start ..ive taken the adapter off and the rest of the screws are in there solid ...dont think thats going to happen lol
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UV light will kill the growth and stop it spreading, but it wont get rid of the growth already there. If you have it professionally stripped and cleaned you may get away with it, but in many cases, removing the fungus leaves an etched pattern in the lens. It's worth getting a professional opinion at least.

You need to be thinking about what's caused it though, unless the lens was infected when you got it. Dark humid storage conditions are the sort of conditions which start these infections off in the first place. Keeping your gear in a normally heated room with adequate ventilation is the best safeguard, and avoid storing your gear in the back of the wardrobe or cupboards in unheated rooms. I keep my gear in a glass cabinet where it also gets plenty of natural light.
 
CT said:
UV light will kill the growth and stop it spreading, but it wont get rid of the growth already there. If you have it professionally stripped and cleaned you may get away with it, but in many cases, removing the fungus leaves an etched pattern in the lens. It's worth getting a professional opinion at least.

You need to be thinking about what's caused it though, unless the lens was infected when you got it. Dark humid storage conditions are the sort of conditions which start these infections off in the first place. Keeping your gear in a normally heated room with adequate ventilation is the best safeguard, and avoid storing your gear in the back of the wardrobe or cupboards in unheated rooms. I keep my gear in a glass cabinet where it also gets plenty of natural light.
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Do you store them without the lens caps on?
 
I don't actually, and that's probably a fair point, although my understanding is that it's a combination of both dark and humid conditions which causes the problem.
 
I would have thought it was fairly unusual in this country? But from what I've heard it's probably not so easy to totally remove it. Which doesn't help of course, sorry.

I wouldn't start pulling the lens apart yourself, do get it looked at professionally.
 
It still amazes me that you can get fungal growth on a glass surface inside a sealed unit. I'd love to know what species of fungus is that's doing the damage.
 
I keep a large bag of silica gel in my kit bag to protect against both humid conditions and condensation when bringing the bag from a cold environment to a warm one.

Dunno if it works but it can't hurt :)
 
Killing the fungus once already there is pretty difficult and a strip down is the best option but even that doesn't guarantee the fungal growth is dead. Replacing the damaged element can also be costly depending on how old the lens is it might be cheaper just getting a new one.

The local Canon approved repair shop in Glasgow told me that you can put it in a hot dry place for a few weeks to kill the growth but then you'll be out of a lens for a while and again it's not a guaranteed solution.

Pretty annoying. I wonder if compact cameras suffer the same problem.
 
ford1 said:
guys i got a sigma 500mm lens and when you look down to the inner lens it has two types of growth on the lens its self..the first lot looks like a clear pollen ..just like clear spots all over and the second type is like a bunch of small brown twigs ..now i read somewhere that uv light can get rid of this but has it by the sounds gone to far
..i can get pictures i think


kev
Click to expand...

You need some Silica Gel to absorb the moisture, keeping your equipment dry will avoid this from happening again.

http://www.silicagelpackets.com/
 
I had some in my 28-70 had to send it to fixation, did a brill job. I now keep some silica gel
in my bags.
I think i got my from going in hot green houses from out in the cold
 
Anyone know where you can get some bags of silica gel? (Some 'bigger' bags than those tea bag sized that come with gear)
 
Most furniture outlet stores will have hundreds of them that came in the packaging from China/India. I`m sure other retailers will have them as well.
 
Type silica gel into ebay and you will find loads.

I bought 500g for £5 now that ford1 has reminded me about the fungus blight :)
 
Remember, that once the gel has absorbed all the moisture it can the gel becomes useless. You'll need to buy and replace regularly or bake them in the oven.
 
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