39mm screw lenses

The 39mm screw mount was introduced by Leica with the model I (C), and used on all the Leica models until the IIIg. The mount was adopted on many Leica copies and other 35mm rangefinder cameras.

The mount is also called Leica Thread Mount (LTM), Leica Screw Mount (LSM), or M39. It is 39mm diameter and 26 threads per inch, with rangefinder coupling.

The most important makers of 39mm screw lenses are:

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

The most important bodies using the 39mm screw mount are:

• Leica I/II/III
• Canon rangefinders
• Voigtländer Bessa
• the Russian Fed and Zorki
• the British Corfield Periflex

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 Russian Zenit, first models