Canon R lens mount
Lens mount for Canon 35mm single-lens reflex cameras / From Wikipedia, the free encyclopedia
The Canon R lens mount is a physical standard for connecting a camera lens to a 35mm single-lens reflex camera body. It was introduced in March 1959 along with the Canon Canonflex.
Not to be confused with Canon RF mount.
The R mount was used on Canon's first single lens reflex (SLR) camera. The mount employed a "breech lock" system to attach the lens to the camera body.[1]
The R mount was discontinued in 1964 and replaced with the Canon FL lens mount.[2] Many mirrorless interchangeable-lens cameras are able to use Canon R lenses via an adapter. The mechanism for controlling the aperture is different from both the later FL and FD mount, although they physically still can mate with most adapters.