What’s that?

m42 is a screw thread mount type used in 35mm SLR cameras and lenses.

It’s been around for a long time and has been used by many manufacturers. It’s simple in design and easy to adapt to most modern cameras.

Most M42 lenses have either preset apertures or a pin that lets the camera stop down the lens before a photograph is taken.

It’s one of my favorite mounts!

History… in short

Developed by Carl Zeiss in 1938 and used in their Praktica line, the M42 mount was later popularized by Pentax in the US. It became a standard, used for decades by German, Japanese and Russian lens and camera makers.

You might see it called:

  • Universal Thread Mount 
  • Praktica Thread Mount 
  • Pentax Thread Mount
m42 mount on Asahi Pentax Spotmatic SP1000
m42 mount on Zenit 12xp

Notable Cameras:

  • Praktica (Carl Zeiss) 
  • Spotmatic (Asahi Pentax)
  • Zenit (Russian)
In 2003, the Cosina owned Voigtländer released the Bessaflex TM, a modern film camera with the M42 mount. (I want one.

Notable Lenses:

  • Flektogon, Tessar, Planar, Pancolar, Sonnar. (Carl Zeiss)
  • Takumar (Asahi Pentax)
  • Jupiter, Mir, Zenitar, Zodiac (Russian)
  • Oreston, Lydith, Trioplan, Domiplan (Meyer-Optik Görlitz, later Pentacon)
m42 mount front view
A picture of a lens mount with a m42 thread.
m42 aperture stop down pin