Archived posting to the Leica Users Group, 2000/02/17

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Subject: Re: RE: [Leica] The Leica Instamatic and M Mount Patents
From: Gaifana@aol.com
Date: Thu, 17 Feb 2000 20:56:10 EST

I'm kind of curious to know how the M mount (or any bayonet mount) could be 
patented after Contax had presumably done it (or introduced it to the 
public). I know I'm looking with U.S. patent law retrospect, but that would 
have never flown today. Perhaps the only reason it was "patented" in the U.S. 
was reciprocity with Germany, which perhaps had weaker patent standards. By 
1952, the bayonet mount was present in Contaxes and Rollei filters, both of 
which predate the M3.

Of course, today, any patent today only lasts 20 years - if today's regime 
had been in place in the 1950s, the Leica clones would have shown up in the 
1970s. 


In a message dated 2/16/00 10:04:40 PM, austin@darkroom.com writes:

<< By the way, 1952 US Patent number 2,618,201 is far more interesting.  That 
is an invention by August Brohl and Ludwig Leitz of an improvement to the 
bayonet mount, used subsequently for the M camera, wherein the invention is 
the addition of alignment indicators on the body and the lens.  In other 
words, this is a patent on the red dots on the lens and body to help align 
the bayonet lugs.  As disclosed, the bayonet mount itself was known and 
thus already in the public domain by 1951.

[Austin] My 1949 Hasselblad has a red dot on the body, and a red dot on the 
lense, to aid in mounting alignment.  Perhaps there is more to the patent 
than the red dots?

- ---------------------

</XMP>

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From: Austin Franklin <austin@darkroom.com>
To: "'leica-users@mejac.palo-alto.ca.us'"
     <leica-users@mejac.palo-alto.ca.us>
Subject: RE: [Leica] The Leica Instamatic and M Mount Patents
Date: Wed, 16 Feb 2000 21:57:34 -0500
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