hazy foggy lens

[luphot]

Hello,
I get an old tessar lens witch has foggy lens (external lens surface)
This is not fungus, dust or greassy material and it doesn't goes with alcool or dish soap.
What is it?
Does anyone have a trick to remove that?
thank you
FP

[E. von Hoegh]

Look at the "fog" with a magnifier. Is it some sort of dirt on the surface, or is it a network of fine scratches?

[Jim C.]

Is the lens scratched so bad that the external surface is hazed like a ground glass ?
You might try a stronger solvent if the lens isn't coated, like acetone or lacquer thinner.

[Fotoguy20d]

Just be careful if its the rear not to get acetone on the bond line

[Louis Pacilla]

Hello,
I get an old tessar lens witch has foggy lens (external lens surface)
This is not fungus, dust or greassy material and it doesn't goes with alcool or dish soap.
What is it?
Does anyone have a trick to remove that?
thank you FP


Hey FP

There is a natural coating that can build up on the outer glass surfaces on aged lens It looks like an uneven coating. This usually does not have a negative effect on image and may add a bit of contrast.

If your looking for a nice soft/sharp w/ gentle contrast in your for portraits and landscape work then I wouldn't worry all that much if you can't get it the haze removed.

Now if your planing on stopping the Ic Tessar down for sharper images then you may see a little lose of contrast but the lens still the Ic should work out just fine.IMHO

BTW- It would help us help you if you could post a photo of the lens surface your having trouble with. Nothing better then seeing what we are asked to diagnose your issue.

[Steven Tribe]

I have heard that lenses that have been stored in dark rooms with diverse fumes, do show a kind of weak etching.
Another possibility is devitrification, which does happen and which I have seen! Horrible.

[luphot]

Thank you all,
It seems not to be on the glass but the glass itself so there might be no solution.

[Steven Tribe]

Devitrification.
No solution, other than melting the glass down and starting from scratch from a blob of glass.