Re: [Leica] Lens Cleaning

[Martin Howard <howard.390@osu.edu>]

Terry Sham jotted down the following:

> I have tried to find the solution from the archives, but no answer was
> found. I know the coating of the front elements of Leica lenses are strong.
> However, how about the rear elements?  Are they softer than the front
> elements? Are they easier to be scratched by cleaning?

OK, easy now: I wasn't trying to imply that the LUG was no place for
beginners.  We've all been newbies at one time or another (myself only two
years ago).

Fact is, you had a whole bunch of questions in your message, the first of
which had to do with materials and techniques for cleaning lenses.  That was
the "contentious" and "unsophisticated" part I was referring to.  That was
also the question to which you can find probably 100 different answers in
the archives.

As to lens coating, I'm sure your right: I don't think it has been discussed
on the LUG before.  I respectfully submit that a better way of framing your
question would have been to highlight the issue of lens coating on rear
elements as the main issue -- rather than burying this in the middle of your
message.  The risk of misunderstanding -- as I did -- is then much less.

I don't know the answer, but I suspect that it doens't matter much.
Speculating for an instance, I would imagine that the lens coating on rear
elements is probably the same (or at least similar) to that on the front.
It would seem more economical from a production point of view to only have
to do one type of coating, rather than many different types.

Secondly, it's rare to have to clean the rear elements.  You pretty much
want to leave these alone as much as possible.  Whenever I've bought a lens
secondhand that's needed cleaning of the rear element, I usually just use a
little ROR on either a lint-free cotton cloth, or a microfibre cloth, and
very, very gently wipe it clean.  Then I never touch it again.  Seems to
work, but then I don't take pictures which require absolute critical
sharpness, 100 l/mm, tripod, enlarged to 20x24", so you mileage may vary.
   
> If they place is not for beginner, where should I go? I really have many
> questions of this kind.

Again, I didn't mean that you (or anyone else) shouldn't ask questions.  We
all learn from good questions and the discussions that follow.  However,
there are a number of almost trivial issues, such as lens cleaning fluids,
lens cleaning materials, UV filters for protection, how to carry an M
camera, which camera strap to use, whether to buy a chrome or a black lens,
and similar issues which have been beaten to death on this list and for
which there is plenty of material in the archives.  You are, of course,
perfectly entitled to ask such questions anyway, but I (and/or others) are
also perfectly entitled to be sick of threads dealing with them and to point
those who ask them in the direction of the archives.

M.

- -- 
Martin Howard                     |
Visiting Scholar, CSEL, OSU       |     It's all about 'interface'
email: howard.390@osu.edu         |
www: http://mvhoward.i.am/        +---------------------------------------