Canon R lens mount

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.
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.
The R mount was discontinued in 1964 and replaced with the Canon FL lens mount.
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.
R lenses.
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