Minolta RD-175


The Minolta RD-175 was probably the first digital SLR which was hand portable. Up until 1995 when this was introduced, the only digital SLR on the market had a very bulky external digital storage system. There were other primitive digital cameras but they were much lower resolution. Minolta combined an existing SLR with a three way splitter and three separate CCD image sensors, giving 1.75M pixel resolution. The base of the DSLR was the Minolta Maxxum 500si Super. Agfa produced a version of the RD-175 retailed as the Agfa ActionCam.
The RD-175 was also notable as the first consumer digital camera to be used professionally, being used to create the full-motion claymation adventure video game The Neverhood.

Technology

Since state of the art CCD resolution at the time was not sufficient for Minolta, the light entering the central 12 mm × 16 mm area of the RD-175's focal plane was compressed by 0.4x relay optics behind the focal plane, similar to the optical reduction system used in the Nikon E series. The light bundled on the smaller sensor area increased the effective sensitivity by 2 stops. Then the light was split and sent to three separate 4.8 × 6.4 mm sized 768 × 494 pixel image sensors, two used for green and one for the red and blue color, reducing the sensitivity increase to about 2 stops. The only usable ISO was 800.
The three images were combined digitally and interpolated to the final size of 1.75 mega-pixels. Images were stored on an internal PCMCIA hard drive. The camera used Minolta AF A-mount lenses with a crop factor of 2.