wrote in message
oups.com...
I don't know if it happens to people here who buy second hand lenses
but I recently had two cameras with the beginnings of fungus on the
lenses that were described as "crystal clear, unmarked optics free from
scratches or fungus etc." Maybe it is just me but I know how fungus
starts. You get a film of grease first that is transparent composed of
hundreds of tiny transparent round deposits. Some time later (could be
years) the blobs are fewer and bigger. Some time after that these blobs
send out filaments and etch the glass.

I just spent five hours working on a Sonnar 180mm f2.8 to get the start
of fungus off the rear of the front element (if I had known how it was
constructed before I started, I guess it would only have taken an
hour). It was very early stage fungus so it hadn't even affected the
coating.

I got a lovely Ikonta with an Zeiss-Opton Tessar lens and that had the
bigger blobs but I cleaned that up and the fungus left only a slight
coating of its own on the glass (it was uncoated anyway so it might
even help).

Have other people come across this grease film in lenses they have
bought? If so, do you think it is fungus or not?

Many times, was cleaned on my knees, (fast, cheap..) and sold for idiots on
eBay