Archived posting to the Leica Users Group, 1996/09/12

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To: leica-users@mejac.palo-alto.ca.us
Subject: Re: number on Summicron focusing ring
From: hartmann@interaccess.com (Nicholas Hartmann)
Date: Thu, 12 Sep 1996 13:43:23 -0600
 
>My 50mm Summicron-M has the number "22" engraved sideways in small
>characters on the focusing ring, just at the end of the metric focusing
>scale.
>
>What does it mean?

I have been told that this indicates the actual focal length of the lens,
in your case 52.2 mm. Apparently even Leica lenses are subject to
sufficient manufacturing variations that their focal lengths deviate from
precisely 50.0 mm, and I suppose the actual focal length has to be taken
into account when calibrating rangefinders.

-- Nick