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

• 20/4 Flektogon
• 35/2.8 Flektogon
• 50/2.8 Tessar
• 58/2 Biotar
• 75/1.5 Biotar
• 80/2.8 Biometar
• 135/4 Sonnar
• 135/4 Triotar
• 180/2.8 Sonnar
• 300/4 Sonnar
• 500/8 Fernobjektiv

Zeiss lenses

Designed for the Icarex TM and SL706:

• 25/4 Distagon (apparently only 20 produced)
• 35/3.4 Dynarex
• 50/1.8 Ultron (concave front element)
• 50/2.8 Tessar
• 135/4 Skoparex

Designed for the VSL-1 TM:

• 50/1.8 Color-Ultron