42mm screw lenses

The 42mm screw mount was introduced in 1947 with the Zeiss Ikon Contax S 35mm SLR, then it was adopted by KW on the Praktica. Later it was chosen by Asahi for the Pentax family of SLRs. It was also used by the Russians on the Zenit. In the 1970s that lens mount became to be old-fashioned, and was progressively replaced by bayonet mounts by all the manufacturers that used it, except on some Zenit. Very recently Voigtländer reintroduced a 42mm screw mount SLR with the Bessaflex.

This mount is also called Pentax screw mount, even if it was not invented by Pentax, or Praktica screw mount (same remark), or shorlty M42.

There were a huge amount of lenses produced in that mount, made by all sorts of manufacturers, and it would be impossible to list them all here, if at all. Only the most important ranges of lenses can be listed.

Carl Zeiss Jena lenses

The first lenses lenses were released for the Contax S. All are auto diaphragm with auto/manual selector unless specified.

• 20/2.8 Flektogon
  • black with diamond pattern, MC
  • black with diamond pattern, electric contacts, MC
• 20/4 Flektogon
  • black with chrome stripes
• 25/4 Flektogon
  • black with chrome ring, rubber focusing ring with humps
  • black with chrome stripes
• 35/2.4 Flektogon
  • black with diamond pattern, MC
  • black with diamond pattern, electric contacts, MC
• 35/2.8 Flektogon
  • alu finish, big barrel, preset diaph
  • black with chrome stripes, focusing to 0.18m
• 50/2.8 Tessar
  • alu finish, big barrel, preset diaph
  • alu finish, bigger barrel, semi-auto diaph with winding lever
  • black with chrome stripes
  • black with diamond pattern
• 58/2 Biotar:
  • black finish, slim barrel, manual diaph
  • alu finish, slim barrel, manual diaph
  • alu finish, big barrel, preset diaph
• 75/1.5 Biotar
  • alu finish, slim barrel, preset diaph
  • alu finish, big barrel, preset diaph
• 80/2.8 Biometar
  • alu finish, big barrel, preset diaph
• 135/3.5 Sonnar or S
  • black with diamond pattern, electric contacts, MC
• 135/4 Sonnar
  • alu finish, big barrel, preset diaph
• 135/4 Triotar
  • alu finish, big barrel, preset diaph
• 180/2.8 Sonnar
  • black finish, preset diaph, changeable lens mount
• 200/2.8 Sonnar
  • black with diamond pattern, MC
• 300/4 Sonnar
  • black finish, preset diaph, changeable lens mount
• 500/8 Fernobjektiv
  • black finish, manual diaph, changeable lens mount
  • leatherette finish, manual diaph, changeable lens mount
• 2x converter
  • black with diamond pattern

Zeiss lenses

Designed for the Icarex TM and SL706:

• 25/4 Distagon (few produced)
• 35/3.4 Skoparex
• 50/1.8 Ultron (concave front element)
• 50/2.8 Tessar
• 135/4 Dynarex

Designed for the VSL 1 (TM), and sold with Voigtländer or Rollei markings:

• 25/2.8 Color-Skoparex = 25/2.8 Distagon
• 35/2.8 Color-Skoparex
• 50/1.8 Color-Ultron = 50/1.8 Planar
• 85/2.8 Color-Dynarex = 85/2.8 Sonnar
• 135/4 Color-Dynarex
• 200/4 Color-Dynarex

These two ranges of lenses are required to activate the open aperture exposure reading of the SL706 and VSL 1 (TM).

The 50/1.8 Color-Ultron existed under the name Ifbagon 50/1.8 to go with the Ifbaflex M102, a name variant of the VSL 1 (TM).