Archived posting to the Leica Users Group, 1996/08/03

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Subject: Re: Coatings on Early M Lenses
From: Marc James Small <>
Date: Sat, 03 Aug 1996 12:24:00 -0400

At 10:38 PM 8/2/96 -0600, Chris Fortunko wrote:

>I will second this. Van Stelten is local and a hell of a nice and competent
>guy. I don't think he does this in his shop in Louisville, since I did not
>see any equipment there. However, the work gets done correctly. I know this
>on "good authority."

REPLY:  John has the work done by a scientific laboratory nearby.

>I did not know about the drip process. However, a friend of mine who worked
>at Leitz in the 1980s, did not think that Leitz coatings were state of the
>art at that time.

REPLY:  Leitz coatings have ALWAYS been "state of the art" insofar as
patents allowed them to be.  I would like to know on what basis your friend
makes this judgement -- did he ever work at, say, Zeiss or Rollei or Kodak
or Wollensak?  He might well know what he's talking about, or he might not,
but I think we're entitled to a precis of his credentials.

>I have a DR Summicron with a superb coating. Could it have been redone? My
>DR looks very good and much different from the other Summicrons (Rigid, DR,
>and collapsible) I have seen. Many of them seem to have a shiny quality,
>which a sales person in Palo Alto attributed to incorrect cleaning.

REPLY:  The NF/DR Summicron dates from 1956 to 1968;  Leitz was using
vacuum-coating techniques by 1960 or thereabouts.  Perhaps your NF/DR lens
is post-1960 and your other two lenses are pre-1960.  As the drip coatings
were moist and soft, they were much more susceptible to abrasion in cleaning
than are later coatings.

>A friend of mine (Robert Benjamin) in Boulder, and a Leica expert (now at
>Jones Drug at Camera),  attributes the bad condition of some of the older
>lenses to overuse of Kodak lens cleaner. He does not recommend the use of
>this particular concoction at all. According to him, RoR should be used at
>most once a year.

REPLY:  Sounds like a great case of more speech than thought.  Maybe we
should stick to what Leitz/Leica recommend and not to what some guy who
works at a Drug Store claims.

Leica has traditionally recommended the use of lens tissues and cleaner,
whether Kodak or not.  They now recommend the use of micro-fibre cleaning
cloths.  Lenses should be cleaned only when they need it, whether this be
once a week or once a decade.

Marc  FAX:  +540/343-7315
Cha robh bas fir gun ghras fir!