Re: [Leica] how to clean a lens

["Dan Post" <dpost@triad.rr.com>]

Seriously folks, and all Dremel Tools aside, you must consider this-
One -the magnesium flouride coating that is deposited on modern lenses is
actually nearly as hard as the glass it is on. Therefore, casually rubbing
with a clean soft cloth is NOT going to hurt it. The only way to take it off
is with an abrasive- I know John Van Stelten uses a cerium oxide, he has
said, that will scrub of the coating, but is not hard enough to cut into the
glass. This is how he cleans elements for re-coating.
Since he ususlly does the older single coated lenses, and doesn't do the
multi-coated, I am not sure if the newer coatings aren't even MORE robust!
Two- scratching comes from a piece of grit- this can be the culprit no
matter how carefully you clean a lens- which is why they say, BRUSH or blow
of the surface first. This will hopefully remove those particles of grit
that can act like sand paper. If there is no oil or grease, or any other
deposit of material that would hold dust, that should suffice. If the lens
has a smear, then a gentle cleaning with a soft piece of uderwear, well
washed linen (my favorite until microfiber- has very little lint!) or the
newer microfiber fabrics will usually get it.
I like the microfiber since it seems to quickly pick up the oil or schmutz
rather than spread it around. I keep all my cloths in a zip-lock bag when
not actually using them to preclude them picking up grit or dust.
I think that one of the biggest culprits in damaging lenses  is the so
called  booklets of lens cleaning tissue- people buy these, toss them into
their bag where all the accumulated grit from every trip you ever took is
lying in wait in the bottom, and as soon as the tissue is put in there, this
dirt seems to jump into and between the many little leaves of paper, and
just lays in wait to scratch your lenses!
The microfiber cloths are a little pricey, but you can wash them out by hand
with a little liquid soap, rinse and hang up to dry- so you can re-use them
for a LONG time!
Nothing special about cleaning a lens- just a little common sense and a
little attention to details like cleanliness!
Dan ( I'm hazy, but not my lenses!) Post
- ----- Original Message -----
From: "Dan Honemann" <ddh@home.com>
To: <leica-users@mejac.palo-alto.ca.us>
Sent: Monday, July 24, 2000 6:30 PM
Subject: RE: [Leica] how to clean a lens


> Well, my post was as much in reply to the others (Ted and Mark, et.al.).
>
> I like the casual approach toward equipment--otherwise, the tools start
> getting in the way of doing the job.  It makes sense to me to leave the
lens
> cap off for the most part, and to avoid using protective filters except in
> extreme circumstances.
>
> On the other hand, if certain solvents (or no solvent at all) harm a lens
> coating, while others do not, it only makes sense to protect one's
> investment by employing the right method when maintaining it.
>
> That's why I'm curious as to just what the right way is.
>
> Dan
>
> B. D. Colen wrote:
> > It was a joke! Joke....Joke!....Although God knows I have often enough
> > breathed on a lens and then wiped it with a cotton shIRt tail....But
don't
> > try this trick at home..:-)
>
>