In 1980, Leitz brought out the R4 and the M4-P at the same time. In the late seventies and early eighties, any mirror reflex camera worths its salt had a adequate motor drive. With their many moving parts, however, these camera systems were loud, and, as autofocus did not yet exist it, were difficult to focus quickly and accurately.
This is where the Leitz rangefinder camera gained the upper hand. The M4-P was extremely quiet, easier to focus even with high speed lenses, and had a silent rewinding lever, making in the quickest and quietest rangefinder alternative, blessed with a bright and contrast-rich viewfinder, smaller dimensions and a comprehensive range of lenses.
The viewfinder's 0.72 enlargement factor also made it possible to superimpose a frameline for wide angle 28 mm lenses. Consequently, the M4-P is an M4-2 with six superimposed framelines for 28 mm, 35 mm, 50 mm, 75 mm, 90 mm and 135 mm focal lengths.
At the same time, the M4-P was the last M without an integrated light meter. The next generation of the M6 already came with a through-the-lens light meter and other electronics.