Leitz engineers would have to wait some time before industrial innovations would allow them to include electric and electronic components for exposure automation into the limited dimensions of the body of an M4-P. The result was the very successful M6 model, though it did have its weaknesses.
The M6's design was defined by clear lines, reflecting the camera's solid functionality and technical precision. Even the outside of an M today is very similar to the M6 from 1984, so that the design has remained virtually unchanged for nearly 30 years.
The M6 offered framelines for six different focal lengths, manual TTL light metering and a standard connection for an external flash. Consequently, the M6's technical specifications were more than sufficient for the type of photography for which it was built. Compared to the technology existent at the time, however, the camera was rather modest. Even so, the M6 was incredibly popular with around 136,700 cameras sold up until 1998.