The ST701 (1971) had TTL stop down exposure metering and was also one of the first SLR cameras with a hot shoe. The ST801 (1972) received TTL full aperture exposure metering, a very bright viewfinder, a fast shutter speed of 1/2000 sec and had a very compact size for its time. The ST901 (1974) and AZ-1 (1978) are the top models in the lineup, featuring an electronically controlled shutter with speeds up to 1/1000 sec and aperture-priority auto exposure mode. 605 series performed TTL stop down exposure metering and had the shortest shutter speed of 1/700 sec, while 705 series offered TTL full aperture exposure metering and the shortest shutter speed of 1/1500 sec.
Fujinon lenses, available for this system in a wide range of focal lengths and speeds, had a modified M42 mount with additional aperture indexing tab and lens locking feature. Full aperture exposure metering was only available with auto diaphragm Fujinon lenses, stop down exposure metering was performed with other M42 lenses.