Fujifilm's Fujica SLR — the ST901, aperture-priority auto, digital LED readout, M42 mount, 1974.
The Fujica ST901 is a 35mm film SLR made by Fuji Photo Film under the Fujica name, introduced in 1974. It was notable as an M42 screw-mount body with automatic exposure, offering aperture-priority operation at a time when most screw-mount cameras were manual-only. It used a digital LED viewfinder readout to show the selected shutter speed.
As a specification summary, the ST901 is a single-lens reflex for 35mm film using the M42 42mm screw mount. It has an electronically-controlled focal-plane shutter, and offers aperture-priority automatic exposure as well as manual operation. Metering is through-the-lens, and the shutter speed is displayed digitally by LEDs in the viewfinder. Because the automatic exposure and shutter timing are electronic, the camera depends on battery power to operate correctly in its auto mode.
The ST901 suits users who want aperture-priority automatic exposure combined with the wide M42 lens pool, useful for travel, street and general photography where speed of use matters. Its electronic auto mode simplifies shooting while manual control remains available. The digital LED readout was an advanced feature for a screw-mount body of its era.
On the used market, note the ST901 relies on its electronics for automatic exposure and the electronic shutter, so confirm it powers up and the auto mode and LED readout respond; a dead battery limits its function. Expect perished foam light seals and mirror-damper foam and budget for a reseal. Test the shutter across speeds, inspect the prism for haze or desilvering, and check the film advance, rewind and focusing screen. The M42 mount gives access to many affordable lenses.