The R mount is the standard method of connecting a lens to the Leica R series of 35 mm single-lens reflex cameras.

[3] On 5 March 2009, Leica announced plans to cease production of its R-Series manual focus SLR and lenses.

[6] These only have the stepped R-cam plus electrical contacts communicating focal length to the camera.

The distance is only 0.5 mm larger than the Nikon F-mount, which is not sufficient to make a workable adapter, however, at least one Nikon camera has been modified with a Leica R bayonet mount to take R lenses,[citation needed] and at least two manufacturers make replacement mounts, allowing many Leica R lenses to be used directly on various camera systems, such as Nikon F mount cameras.

The mounting flange may then need to be machined to allow free movement of the remaining cam.

A further point of consideration is whether the protrusion on the rear lens block will engage with the mirror of the target SLR.