90 mm Summicroon-R with small spot of fungus. Salvageable or paper weight?

[spoolman]

I just had given to me a Leitz Canada 90mm f2 Summicron-R lens with a 1mm. diameter spot of fungus on the inside element in the middle. Is it worth getting cleaned or is it a paper weight?

Doug

 

[blee1996]

A competent service person can easily remove the small fungus, no need to worry too much if it is a new growth and relatively small.

 

[hospadar]

If you decide it’s a worthless paperweight I’ll take it for my windy desk

I just cleaned some (more significant but not extreme) fungus out of an old cannon 100/3.5 LTM. Usually it’s a pretty easy job to open up a lens for cleaning, the main thing is to not slip with the spanner

Usually fungus will etch or damage the coating on the surface it’s growing on, so cleaning is good and will prevent further growth but there probably will be a teeny bit of damage, though i suspect for such a small spot you’ll never know the difference. My 100/3.5 had fungus etching on probably 10-15% of one of the interior surfaces and the shots came out looking sharp and great. Theoretically you might notice some more flare but i suspect if it were cleaned and you didn’t know it was there you’d never think twice

 

[Marcelo Paniagua]

Depends if fungus left an etching on the lens AND your definition of salvageable.

Some years ago, my Leica Summilux 35mm grown some fungus. DAG cleaned the fungus but it left a haze like mark. While lens was still usable at smaller apertures, haze made images contrast less and hazy on full open (which was why I got the Summilux). It became useless to me but it was usuable to someone else so sold it.

I would advise to get it cleaned. I had that lens and used on my digital for a time and it was very good. Also, lens is quite big and fungus is still small and would say image impact is small. My worry would be that fungus will expand further and make more damage.

 

[Andreas Thaler]

If the fungus spot is so small, I would just observe it; it won't affect the image.

I would only open the lens if the fungus were to spread. But for that, it needs living conditions - moist, warm, dark.

Perhaps it's no longer active at all.

 

[spoolman]

If you decide it’s a worthless paperweight I’ll take it for my windy desk

I just cleaned some (more significant but not extreme) fungus out of an old cannon 100/3.5 LTM. Usually it’s a pretty easy job to open up a lens for cleaning, the main thing is to not slip with the spanner

Usually fungus will etch or damage the coating on the surface it’s growing on, so cleaning is good and will prevent further growth but there probably will be a teeny bit of damage, though i suspect for such a small spot you’ll never know the difference. My 100/3.5 had fungus etching on probably 10-15% of one of the interior surfaces and the shots came out looking sharp and great. Theoretically you might notice some more flare but i suspect if it were cleaned and you didn’t know it was there you’d never think twice

Hello: I tried to clean it myself. I removed the lens hood and the retaining ring but the element refused to come out and I didn't want to force it.

Doug

 

[Marcelo Paniagua]

Hello: I tried to clean it myself. I removed the lens hood and the retaining ring but the element refused to come out and I didn't want to force it.

Doug

Wise. It is too easy to break things that seem stuck

 

[blee1996]

I worked on a much cheaper M-mount Elmar 90/4 lens for cleaning, and I used those lens suction tool to remove the glass elements. Safe and clean. Sometime I did need to wiggle a little bit since the seating can be quite tight.

Leica tolerance is tight (high precision), and the construction is very sensible and service friendly.