Oil on glass?

[manfromh]

Hello

I have a m42 mount Helios-44, which has some weird formation on glass. At first I thought its fungus. The aperture blades are very oily and the lens even smells of oil. So does anyone have a picture of what oil on glass looks like, or what fungus looks like? The formation does look kind of like a spiderweb, but it hasnt spread at all since I got the lens last summer. I dont know how fas fungus spreads.

Thanks
Matis

Edit: Whoops, I only now noticed that there is a repair forum too.

 

[Xmas]

Matis

Its not that it spreads quickly but its by product is sufficiently acid to eat most optical glasses, and it (in my experience) is more random than most spiders webs.

If you like the lens and it is fungus it is file the ends of your needle nosed pliers next weekend.

I've also had condensation damage glass surfaces, some of the optical glasses are really intolerant of anything.

Noel

 

[manfromh]

I compared the lens to some images I found on the internet. Now im more convinced its fungus. Luckily those lenses are very cheap.

Matis

 

[Pablito]

spiderweb = fungus.

I have seen a lot of fungus. Used to live in a very humid climate where fungus was practically guaranteed.

 

[FallisPhoto]

I compared the lens to some images I found on the internet. Now im more convinced its fungus. Luckily those lenses are very cheap.

Matis

More often than not it can be cleaned off, with a 50/50 mix of hydrogen peroxide and ammonia. It takes a while for the fungus to eat into the glass and most of the time people give up on a lens before getting all the fungus off, assuming that the filaments of fungus are etched into the glass when they are not (they just haven't gotten all the fungus off). The aforementioned hydrogen peroxide/ammonia mix will literally melt it away. However, it should not be used full strength on lenses made before the mid 70s, particularly on Leicas. In those days, they hadn't discovered that baking lenses fuses the coating to the glass and the lens is likely to be softcoated. Baked lenses were not in common usage until about 1975 (first done on Pentax lenses sometime around 1970). In this case a 2% to 5% solution is recommended (by Leica).