Archived posting to the Leica Users Group, 1996/12/14[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]
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 email@example.com FAX: +540/343-7315 Cha robh bas fir gun ghras fir!