Leica R mount lenses

introduction

these are manual focus, bayonet mount lenses designed for the Leica R 35mm film SLR cameras and as such they tend to be quite large and heavy, although generally, of high optical quality, especially the apochromatic ones such as the 90mm f/2 AA, 100mm f/2.8 Macro, 180mm f/2, 180mm f/2.8, and 280mm f/4.
flange focal distance between mount and film is 47 mm
these can be used via adapters on most digital cameras with interchangeable lenses EXCEPT for Nikon (unless the camera has been modified)
although they can be used on Micro Four Thirds system, their size makes them more usable on a Canon EOS camera system however, there may be issues with the Canon full frame mirror and some of the wider angle lenses.