Hi all,
As you may have read over the past two weeks in the "Cleaning an OM300/4.5
lens" thread, I attempted to get rid of the fungus in that lens, here are my
experiences:
Over the Easter holiday I performed the surgery on the lens, closely
following the guidelines provided to me. First I tried to remove the whole
frontal part of the lens by unscrewing the 3 small screws that are located
under the lens shade hood. Unfortunately, the frontal part is glued tightly
to the rest of the lens, so I couldn't separate these two parts as a whole,
and I didn't really fancy attempting to use glue solvent.
Therefore I decided to try to reach the 2nd element from the front, after
all, when looking through the front of the lens, the fungus appeared to be
on the top of the 2nd element. So I screwed off the lens info ring and
dropped out the first element. Much to my surprise, the fungus was not
located where I thought it would be, but instead I ran into the 2nd element,
which was clean. Now it appeared the fungus was located one level lower,
i.e. on the top of the third element. Carefully progressing, I removed the
2nd ring and dropped out the 2nd element, again to find that I had been
fooled again by appearances, as the fungus isn't located on top of the third
element either.
It is really amazing how you can be fooled by looking through the front of
the lens, as I could have sworn it was located on the top of the 2nd
element. By now I know that it must be located either on the bottom of the
4th element, or in the worst case in between the 3rd and 4th element which
are glued together (which would mean "game over" as there is no way I'm ever
going to attempt to separate such elements)...
Since I couldn't reach the fungus from the front I decided to re-assemble
the lens, so I took the lot to the bathroom to limit the amount of dust. I
then carefully cleaned the second element so there was no dust and dirt on
it and put it between a special kind of paper which you can buy at photo
stores (the kind which doesn't leave paper particles when using it). Then I
cleaned the inside of the lens (using a canister of clean air and a dust
free piece of cloth. Then I very carefully lowered the 2nd element in place.
This is where the trouble happened: the element didn't directly get in
place correctly and therefore I carefully moved it around a little bit so it
would get in place properly. In order to do so, I (again, very carefully)
more or less clamped the element from two sides between two semi small
screwdrivers so as to properly move it into place. This worked, but at the
moment the element went into place, a small piece of glass (+/- 0.5 cm by
0.5 cm) chipped off the back of the second element, AAAAARRRRGHHHHH -I felt
like dying-. :(
I don't understand how that could happen exactly, as the screwdrivers didn't
even touch the glass over there, and I used the utmost care, so it's not
like the element was forced into place or something.
Anyway, the damage was done and now there was glass between the 2nd and 3rd
element, so I removed the second element again, cleaned the lens again and
tracked down a "suction nap" (what do you call these things exactly?) from a
clothes hanger, and used that to put the element back in place. This went
remarkably well and without further damaging the lens, so I wished I had
thought of that before.
Well, after that I cleaned the rest of the lens and put the first element
back in place using the suction nap.
Unfortunately, now the lens is in a worse condition than it was before my
attempt to clean it. I looked through the viewfinder from all sorts of
angles to check if the newly introduced damage would show, but I couldn't
see it. So far I haven't seen any picture degradation on the actual photos
either, but the weather conditions weren't perfect and as the sun didn't
show up I haven't taken a counterlight picture yet. Hopefully I can get away
with the damage, as it is not a very big piece of glass that got chipped
off...
Well, obviously the above experience has made me think twice about doing
this stuff myself, so I'm not certain yet whether I should or shouldn't mess
with glue solvent to try to separate the two half-lenses. It sounds like a
tricky task to remove the glue, so before even thinking about attempting
that, I'm going to need some professional/experienced opinion about it
(John, feel free to drop in here).
The moral of the story: use the utmost care and the right tools when
attempting to do something like this yourself. In my case the problem came
from not having the right tools (as I have cleaned/repaired far more fragile
objects before in my life), rather than being uncareful. Probably it's best
to leave it up to the professionals, as it is also a quite a pain to
eliminate the dust in the lens. However, being an engineer I just had to do
it myself... :)
So for now I'm going to leave the lens "as is" unless someone can tell me if
it's easy to use glue solvent. Also, if someone on the list perhaps knows of
a way of getting a replacement 2nd element (maybe from a damaged lens
someone might have?), I would be very interested. Maybe Oly even sells these
elements separately, but I'm guessing that will be _quite_ expensive...
Good, despite the unfortunate outcome it has been a learning experience, and
at least now I know how to _do_ go about cleaning these things (although I'm
not sure I'd attempt it again), so I still think it was worth a shot.
Cheers!
Olaf
PS: Marco and others: many thanks for the tips on how to go about cleaning
the lens, it would have been more complicated without those descriptions.
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