39mm screw lenses

The 39mm screw mount was introduced by Leica with the model I (C), and the lenses became coupled to the rangefinder with the model II (D).

Later the mount was adopted on many Leica copies and other 35mm rangefinder cameras. The Leica screw mount was 39mm diameter and 26 threads per inch, but some makers adopted a mount with 39mm diameter and 1 millimeter thread, which could cause trouble.

The most important makers of 39mm screw lenses are:

• Leica
• Canon
• Zeiss, some rare lenses
• Nikon, some uncommon lenses
• Russian makers like Fed or Krasnogorsk
• Voigtländer today, in the Cosina period

Some makers made cameras and lenses with a 39mm screw mount completely incompatible with the Leica one, because the flange-to-film distance is different. Two such systems are:

• the Braun Paxette
• the first Krasnogorsk Zenit models