Archived posting to the Leica Users Group, 1993/04/23

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To: jeff@eng.umd.edu
Subject: Summicron lens ID-6 or 7 or 8?
From: Aaron Heller <heller@ai.sri.com>
Date: Fri, 23 Apr 93 13:34:33 PDT
Cc: leica-users@mejac.palo-alto.ca.us


   Date: Thu, 22 Apr 1993 08:01:45 -0400
   From: Jeffrey Frey <jeff@eng.umd.edu>

   How can I tell whether my 50/2 Summicron (Screw-mount) has 6 or 7
   elements (or is it 7 or 8?)?  If you have the answer, where did you
   find it?


According to van Hasbroeck (Leica -- A History Illustrating Every
Model and Accessory), the 50mm Summicron is a modified 7-element Gauss
computation.

He also notes that it was recomputed with 6 elements in 1971, with
focusing to 0.7 meters.  However, if yours is the screw-mount model,
you don't have this one.

Also, Morgan (Leica Manual and Data Book, 14th edition, 1961) has a
cross section of the 50mm Summicron which shows 7 elements in 6
groups.

Aaron

P.S. Does it happen to be the rigid model?  Only 1000 of those were
made.

--
Aaron Heller, EK264        Internet: heller@ai.sri.com
SRI International             Phone: 415/859-2618
333 Ravenswood Ave.             Fax: 415/859-3735
Menlo Park, CA 94025

In reply to: Message from Jeffrey Frey <jeff@eng.umd.edu> (Summicron lens ID-6 or 7 or 8?)