Archived posting to the Leica Users Group, 1996/08/02

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Subject: Coatings on Early M Lenses
From: Marc James Small <>
Date: Sat, 03 Aug 1996 00:22:33 -0400

Leitz was not granted permission to use the Zeiss vacuum-coating technique
developed by Alexander Smakula and patented by Zeiss in 1936 and 1940;
thus, Leitz used a drip process which produced a much moister and softer
front coating  -- many lenses of the period from the lesser manufacturers
were coated on internal elements only for this very reason, though I cannot
recall that Leitz ever did so.  The Zeiss patent expired, I believe, in
1960, and Leitz was vacuum coating their lenses shortly thereafter.

These coatings dry out with time and need replaced.  John Van Stelten in
Louisville Colorado does this for about $100 a lens.  He's efficient and
quick, and the results can be astonishingly good.

This is a handy buyer's point:  many dealers don't understand the history of
technology, and simply ascribe the dried coatings to 'wipe marks' and
discount the lens substantially.  Shop around, and you can get some buys.

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