Minolta RD-175

Minolta RD-175

Image of the Minolta RD-175
Type	Digital SLR camera
Focus	Automatic

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. ^[1] The base of the DSLR was the Minolta Maxxum 500si Super (the Dynax 500si Super in Europe and as Alpha 303si Super in Asia). 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 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 × 16mm 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 (ISO) by 2 ²⁄₃ stops. Then the light was split and sent to three separate 4.8 × 6.4mm sized 768 × 494 pixel (3 x 0.38 megapixel) 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.^[1]

The three images were combined digitally and interpolated to the final size of 1.75 mega-pixels (1528 × 1146 pixels). Images were stored on an internal PCMCIA hard drive. The camera used Minolta AF A-mount lenses with a crop factor of 2.

See also

• Nikon E series
• Telecompressor

References

External links

• RD-175/Agfa ActionCam review by John Henshall
• Agfa ActionCam on Jarle Aasland's NikonWeb.com site
• Example images at Pbase.com