The M4 replaced the dozen year old design of the M3, as well as that of the M2. It incorporates framelines for 35, 50, 90 and 135 framelines. The rewind lever is mounted at an angle with a folding crank to facilitate rapid rewind, especially while a meter is mounted on the camera. M4 cameras also have the rapid load systems introduced on the M2R. Some M4 cameras were designed for use with motor drives, and are marked M4M or M4 MOT. A batch of 31 cameras were finished in olive green in 1970 (but were listed in the statistics as black). In 1975 1750 M4 cameras were engraved with a 50 Jahre (50 year) logo to commemorate 50 years of Leica production.

See recent price change history for the Leica M4.