Leica M39
A threaded lens mount standard used on Leica rangefinder cameras, also known as Leica Screw Mount or LTM.
Overview
The Leica M39 is not a camera model. It is a screw-thread lens mount that Leica used on its rangefinder cameras from approximately 1923 to 1965. It also goes by Leica Screw Mount (LSM), Leica Thread Mount (LTM) and L39. The mount was built for rangefinder lenses, so alignment and focusing work as they should. During this period Leica offered factory upgrades, which let owners modernize earlier models and keep their original serial numbers. Cameras assembled at the Midland facility (Ernst Leitz Canada) were rarely engraved with "Midland."
Specifications
| Flange focal distance | 28.8 mm |
| Product type | camera lens mount |
Design
The Leica M39 is a screw-thread mount made for rangefinder lenses, not SLR systems. It is mechanically different from the Soviet M39 mounts, which use a 25.4 TPI thread. The two look alike but are not compatible.
Context
Lenses designed for SLR systems, such as the Mir-1B, cannot reach proper focus on the Leica M39 mount because of optical and mechanical mismatch. The Leica M39 standard is not interchangeable with Soviet M39-threaded cameras like the Zenit or Chaika, which differ in thread pitch and flange distance. Adapters to other systems, such as the M bayonet, may disrupt rangefinder coupling and hurt focusing accuracy.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.