[citation needed] Early Canon cameras also used a different M39 × 24 tpi thread mount, called "J-mount".

The Soviets later adopted the LTM mount for their Zenit single-lens-reflex (SLR) cameras, though with the longer optical registration of 45.2 mm, required to allow the mirror room to flip out of the focal path when a picture was taken.

The LTM system was tested at the request of Leitz on lenses manufactured in small batches by Hugo Meyer in Germany and marketed with a run of Leitz cameras by A. O. Roth in London.

Currently, Cosina in Japan — many of whose recent products are marketed under the Voigtländer brand — and FED in Ukraine continue to produce camera bodies using a true Leica thread-mount.

Adaptors are available to use M39 lenses with modern digital cameras, such as the Canon EF-M, Sony E or Nikon Z mounts.