Archived posting to the Leica Users Group, 1996/12/14

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Subject: Summicron & Genealogy
From: Marc James Small <>
Date: Sat, 14 Dec 1996 10:25:35 -0500

Here be the tree of the family of the 50mm Summicron:

FIRST GENERATION:  seven elements in four groups
collapsible (TM '53 to '60 and BM '54 to '57) 
rigid (TM '60 to '63 and BM '56 to '68) slightly different optical design
from the         collapsible model
NF (or DR, if you prefer) (BM '56 to '68) identical optically to the rigid
model, but           with eyes which, when added, allow 'near focusing' (NF)
thus making it a                'dual-range' (DR) lens

SECOND GENERATION:  six elements in five groups (BM only, '69 to '79)  a
completely         different design which should have been renamed

THIRD GENERATION:  six elements in four groups
without lens hood ('80 to '94?)
with inbuilt lens hood ('94? to the present)  (I do not know the precise
year of the         changeover to the inbuilt hood)

I hope this straightens things up!  We really have three distinct optical
designs here, and ought to have had three different lens names.  Leitz/Leica
confused the issue by carrying over the old name on a new lens (as they did
on so many other designs as well, though!)

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