View source for F2.0

Leitz lenses of 35mm length with f 2,0 aperture have always bore the brand name SUMMICRON; this name, which firstly was used for the 50 mm f2 lens announced in 1954 together with Leica M3, during the years has became the standard name for any f2 lens, in a focal range that for Leica M bodies extends from 28mm to 90mm

So, from its introduction in 1958, the role of the 35 f2 for RF Leicas has been played by 2 lenses only :

- The Summicron 35 f2 during about 40 years (1998 last production - in later years the complete
  name was indeed Summicron-M)
- The Summicron 35 f2 Aspherical from 1997 onwards

BUT, the long life of the Summicron 35 f2 has been very complicated, with many versions, various basic lens design, many different details even in the same version, and an adequate number of codes. A complete dissertation on this topic would take many pages, and anyway the whole story is well narrated in some specialized books (principal authors: Lager, Laney, Rogliatti, Sartorius, Van Hasbroek. To give an idea, one can estimate that, apart prototypes, an hipotetical collection of Summicron 35 could easily include at least 30 lenses that are different in something besides the serial number.

The very first version of Summicron 35 was made also for Leica screw mount bodies : the production was limited (in the range of 500 pieces, but even this scarce version has a (little) number of variants.