The Canon FD lens mount was used by Canon, it’s a breech-lock type mount.
Instead of the lens going into the camera body and locking, the camera body has a protrusion, which goes into the lens. A turn of a mounting ring secures it in place.
The Canon FD mount replaced the Canon FL mount, which is also breech-lock. FL lenses are compatible with FD film bodies.
History… in short
The Canon FD mount was created in 1971, replacing and improving Canon’s previous lens mount – the FL lens mount.
Canon aimed for a full camera system, with a lot of accessories. A lot of high quality lenses were made in Canon FD, including “L” (Luxury) lenses which were created to a really high quality and performance standard.
- Canon F1
- Canon T series
You’ll most often see a distinction between Canon FD and Canon nFD lenses.
- Canon FD lenses are older and most often heavier and made of metal.
- Canon nFD lenses have better coatings and improved designs, bundled together in a smaller package due to the use of plastic.