A 35mm film SLR system that not only inherited both spot and average metering systems from the earlier Mamiya DTL series cameras, but also added shutter-priority automatic exposure (with manual override) and TTL open-aperture metering. This, however, required the abandonment of the M42 screw mount and the introduction of a new bayonet-type mount. Mamiya produced two cameras for this system: the Mamiya/Sekor auto XTL and the Mamiya AUTO X1000 (without "Sekor"). Both had identical specifications, and differed only in finish, which was black-and-chrome in case of the auto XTL and professional all-black for the AUTO X1000. It was planned to release a motor drive for the auto XTL, however, due to the fact that the system was actually ahead of its time and did not gain popularity, the motor drive was never put into production.
Mamiya produced an extensive range of Mamiya/Sekor ES lenses for this system, from the ultra-wide angle 21mm to the super telephoto 800mm. Most of them had automatic diaphragm, and only the super telephotos were equipped with preset diaphragms. The ES lenses had a unique tapered barrel design so that fingers could find aperture and focusing rings by feel alone. Fluted rubber focusing rings provided secure grip for removal and finger tip focusing.