Originally Posted by Grytpype
I'm sure if it was fungus, vinegar (or your 'medicinal' acetic acid) should shift it. Have you tried solvents (e.g. lighter fuel)? On at least one occasion I have successfully removed marks that resisted all other methods using cellulose paint thinners, with no ill effect on the lens or coating.
Yes, acetic acid is very effective against fungus. The doctors say that it doesn't work on nail fungus if the whole nail is infected down to the root. I've been treating it for a year, and now a healthy nail is growing out.
The alternative was strong antifungal medicine that can affect the liver.
Good idea, I will try heptane. I had good luck with it before when isopropanol didn't clean the glass properly.
Originally Posted by fidget
It doesn't look like the fungus that I have cleaned off several lenses, that had soft edges to the blobs and the odd strand running out from some. You are right to be cautious about dunking the lens, I once did and ruined a cemented lens pair.
The camera (IB) seems to have been stored in a damp place for a while, since I found small corrosion marks on a steel ring (that transfer the aperture settings to the numbered scale).An earlier owner had tried to "repair" the shutter with too much oil and used grease even on the shutter retaining ring.The shutter didn't work, and focus was off. I already have Retinas of this type, but it's fun to try to get non-working ones into shape.