Just under 60,000 models of the Leica M4 were produced in the time from 1967 to 1975, around 9,000 of which had a black-lacquered finish. As well as combining features of the M3 and the M2, the new model also offered a number of improvements in terms of handleability.
For example, loading film was made far more straightforward, as the film no longer had to be intricately threaded onto the take-up spool. Instead, the removable spool of previous models had been replaced with a quick-load spool that automatically grabs the film leader. Shutting the camera's base plate pushed the film into the correct position, at which point (as with the M3) the frame counter reset itself to zero.
The M4 also introduced a redesigned film advance lever as well as a new, angled rewind crank.
The M4's viewfinder represented yet another technical improvement: framelines for a focal length of 135 mm had been added to the popular wide-angle rangefinder originally featured on the M2 – making the M4 the first model of the M series to combine the focal lengths of 35 mm, 50 mm, 90 mm and 135 mm.