"Collin Brendemuehl" wrote in message
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"Richard Knoppow" wrote in
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"Collin Brendemuehl" wrote in
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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.
Richard,
Thanks for your thoughts.
I was mostly concerned about touching the interior
surfaces at all.
I don't know if there's any interior coatings on the old
Fujinon W
210/5.6.
If so, then I'm not too worried about marks, but would
take obvious
care to
prevent them anyway. If not, then the possibility of any
marks would
be very important and leaving any marks would be a big
negative.
Do you know if the interior surfaces of a Fujinon W are
coated at all?
Collin
I think all Fujinon lenses are hard coated. The only
non-experimental soft coated lenses I know of were some of
Kodak's Ektar series made in the early 1940's These include
the Eastman Ektar series (predecessor to the Commerical
Ektar), the lens for the Medalist camera, the lenses for the
Ektra 35mm camera, and for a couple of other deluxe lenses.
After about 1946 all lenses were coated using vacuum
deposition technique forming hard coatings. hard coatings
are often more easily scratched than the glass they are on
but can not be wiped off. In fact removing them is something
of a problem. I would use great care on internal surfaces,
but then I recommend that for external surfaces also. So
called cleaning marks come from abrasive on the cleaner. I
recommend not using anything re-usable on a lens: not
brushes or microfiber cloth or anything else which gets used
twice. Use good quality lens tissue or Kimwipes. For
brushing use lens tissue. Roll it into a tube, tear the tube
in half and fold the feathered ends together. Use that ONCE
and toss it. Don't use the inside of your tie or pocket
handkerchief or any of many similar things I've seen used.
Scratches DO count. One will not ruin a lens but the sort of
marks that look like a lens has been cleaned with a Brillo
pad destroy both contrast and sharpness.
--
---
Richard Knoppow
Los Angeles, CA, USA