[Dukeatoakland]

Many months ago I received a SMC M 50 1.7 as a throw in with an Super Tak 50. It was in sad shape. The aperture closed occasionally. The focus ring had variable resistance. I think one of the colonies of fungus was attempting to annex an adjacent element under the pretext of historical ties to the colony on said element. It was bad. I wrote this lens off as a lost cause. Then I thought, I can use it as a study lens.
After many hours on youtube I was under the delusion that I could save the troubled lens. It gets worse. I followed every corroborable piece of advice I could get. After a few hours in surgery the lens was reassemble and tested. It worked! Everything worked! It was clean, fungus and scratch free. Now, a few months later the truth sets in. There are tons of cleaning marks on the internal elements. These marks were undetectable after the rehab. Is this normal? I'm not worried about this particular lens. It works and I can't detect the marks on the final image. But I am concerned about not being able to detect scratches for such a long time after cleaning. Is this an oddity to this lens or did I just fail to detect them. Why would they be so much more pronounced after a few months? I'm going to find another junk lens and have another go at it. I would like to hear from anyone that has had better success.

[Sagitta]

Many months ago I received a SMC M 50 1.7 as a throw in with an Super Tak 50. It was in sad shape. The aperture closed occasionally. The focus ring had variable resistance. I think one of the colonies of fungus was attempting to annex an adjacent element under the pretext of historical ties to the colony on said element. It was bad. I wrote this lens off as a lost cause. Then I thought, I can use it as a study lens.
After many hours on youtube I was under the delusion that I could save the troubled lens. It gets worse. I followed every corroborable piece of advice I could get. After a few hours in surgery the lens was reassemble and tested. It worked! Everything worked! It was clean, fungus and scratch free. Now, a few months later the truth sets in. There are tons of cleaning marks on the internal elements. These marks were undetectable after the rehab. Is this normal? I'm not worried about this particular lens. It works and I can't detect the marks on the final image. But I am concerned about not being able to detect scratches for such a long time after cleaning. Is this an oddity to this lens or did I just fail to detect them. Why would they be so much more pronounced after a few months? I'm going to find another junk lens and have another go at it. I would like to hear from anyone that has had better success.

If you had fungus, it probably ate at the glass and scored it. I'd assume you may have failed to completely nuke all of the squatters so they're trying to re-establish Fort Fifty once again, and in the process are becoming visible.

[Dukeatoakland]

I'd assume you may have failed to completely nuke all of the squatters so they're trying to re-establish Fort Fifty once again, and in the process are becoming visible.

I like this theory. Maybe I'll just have another go at this lens and see if history repeats itself.

[Edgar_in_Indy]

How do you clean the elements? Zeiss sells some lens wipes at Wal-Mart and elsewhere that seem to do a pretty good job, although I'm not sure if they're much more than glorified alcohol towelettes. But they seem to be completely lint free.

[Dukeatoakland]

I used 91% isopropyl alcohol and surgical cotton, followed by air.

[BlakeShellman]

I used 91% isopropyl alcohol and surgical cotton, followed by air.

Maybe the fungus enjoyed being under the influence?

[bobpur]

The cleaner you used may have left a residue that caused a little fogging, use a new lens pen after the cleaning.

[pentaxus]

ROR is a good cleaner for this kind of stuff as it contains a bit of ammonia that fungus doesn't like. Kimwipes work well with ROR. Pentax lenses generally clean up pretty well since all surfaces are hard coated. Some other brands use softer coating inside since "nobody will clean in there". The fungus is there to eat the delicious coating so sometimes you will see irregularities in the coating after cleaning. A little bit of splotchiness doesn't generally affect pictures too much but looks ugly and drastically reduces value.

[Sorver]

Maybe the fungus enjoyed being under the influence?

Lol like your thinking