"Collin Brendemuehl" wrote in message
om...
This is something that doesn't frighten me technically
speaking.
But I find it generally prudent to ask about matters that
will cost
more than $20 to experiment with.

I found an old Fujinon WS 210/5.6. The single-coated
version.
Inside the front cell, in the air space, is some fogging
on the glass.
Inside the rear cell, in the air space, is some edge
fogging.
(The only thing that makes me hesitant about taking this
on is the
presence
of some cleaning marks on the rear cell.)

So I checked Kerry Thalmann's online Fuji brochures to
verify (and it
proved true)
the open air space within each cell.

While opening the cells won't be a real issue, my concern
in cleaning
methods.
What would be an appropriate approach to cleaning fog off
cells and
subsequently keeping the interior appropriately clean?
My first thought is standard lens cleaning fluid. Just
keep it wet to
avoid
marking it. But this may or may not be adequate.

Has anyone done this, or are you all too scared?

Or should I see about getting a better bargain and try to
get the
cells cheaply enough to justify the experiment?

Your thoughts?

TIA,

Collin (the bargain hound) Brendemuehl

Clean them just as you would outside surfaces. Lens
cleaning fluid or 99% Isopropyl alcohol are fine. Use lens
tissues or Kimwipes and use each once only. Blow out the
cell after cleaning it and before putting the lens back. If
a lens doesn't come out easily try lifting it out with a
piece of scotch tape. If the surface is clean that won't
hurt it. Becareful to note any shims and get them back
properly. Few old lenses had shims but some modern ones do.
If the cells have threaded back caps they are very easy to
open. Most lenses without back caps have threaded front
retaining rings. The best way to remove these is with a
friction tool made of a soft rubber ring cemented to a tube
the right diameter. Be careful replacing the lens. The
clearances are very small and you don't want to chip the
lens by forcing it. It must displace some air going in so
will move slowly.
I don't know for certain what causes the haze in lenses
but think its probably some residual volitile material from
the anti-refection paint on the inside of the cell. Some
makes of lenses seem more prone to develop it than others.
Schneider and Kodak lenses seem to have haze frequently.
Some very old lenses may even seem to have soot inside.
I've found this stuff also cleans right off with lens
cleaning fluid and leaves the lenses sparkling clean.
Even a small amount of internal haze will destroy the
contrast of a lens. I think one reason that uncoated lenses
have a reputation for being very flary is due to interenal
haze and dirt. They really are not that bad.


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Richard Knoppow
Los Angeles, CA, USA