Difference between revisions of "Minolta RD-175"

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The '''Minolta RD-175''' (also sold as the '''Agfa Actioncam''') was one of the first digital [[SLR]] cameras. When [[Minolta]] introduced this camera in 1995 it did cost a very huge amount - around $10,000. At that time the Minolta engineers used a costly trick to get good colour pictures in 1.75 [[megapixel|mega-pixel]] resolution: The light which got through the lens had to be ripped into red, green and blue light parts<ref>Possibly not RGB, but two green + one red/blue</ref>. Each part was projected onto its own [[CCD|CCD light-sensor]]. So the camera included 3 CCDs which worked together for making colour pictures.
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The '''Minolta RD-175''' (also sold as the '''Agfa Actioncam''') was one of the first digital [[SLR]] cameras. When [[Minolta]] introduced this camera in 1995 it cost around $10,000 US, inaccessible to Minolta's usual base of amature and enthusiast photographers, intended for professional business markets (including medical, insurance, and scientific) in which Minolta had made scant little inroads at the time.
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The CCDs had a resolution of 768 x 494 pixels, which was interpolated out to 1,528 x 1,146.
 
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The resulting 1.75 megapixel images were stored on a PCMCIA type III hard disk card.
 
  
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The handling of the camera was almost like that of other autofocus SLR cameras of the time, and the lenses for this camera were simply the same as the ones for Minolta's Maxxum/Dynax/alpha camera bodies. The picture quality, once praised, is far behind that of [[Konica Minolta]]'s digital SLRs with 6 mega-pixel resolution.
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Minolta engineers used a costly tricks to get acceptable colour pictures in 1.75 [[megapixel|mega-pixel]] resolution:
  
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<references />
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1 - Relay optics reduce the image size from Minolta's normal 35mm SLR lenses from 36 x 24mm to 16 x 12 mm, about 1/2 or ~0.5x, (doubling the effective focal length) and reducing the e widest effective aperture to f/6.7.
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2 - The light which got through the lens was split using a dichroic prism block split the image-making light into the required components for each sensor.  Each part was projected onto its own [[CCD|CCD light-sensor]].
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3 - They used two green sensors, and one red/blue combination sensor, which was striped using a microscopic filter elements.  This made the camera back huge compared to film SLRs. Each CCD has a resolution of 768 x 494 pixels on 6.4 x 4.8 mm chips (~3.6% area, or ~19% linear of the size of 35mm film).
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4 - Then the three images were digitally integrated and interpolated out to 1,528 x 1,146 pixels, ~1.5x.  The resulting 1.75 megapixel images were stored on a PCMCIA type III hard disk card.
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The handling of the camera was almost like that of other autofocus SLR cameras of the time, and the lenses for this camera were simply the same as the ones for Minolta's Alpha/Dynax/Maxxum film SLR camera bodies. The picture quality, once praised, is far behind that of [[Konica Minolta]]'s later digital SLRs using Sony's single-chip 6 mega-pixel resolution.
  
 
== Links ==
 
== Links ==

Revision as of 12:22, 20 October 2008

The Minolta RD-175 (also sold as the Agfa Actioncam) was one of the first digital SLR cameras. When Minolta introduced this camera in 1995 it cost around $10,000 US, inaccessible to Minolta's usual base of amature and enthusiast photographers, intended for professional business markets (including medical, insurance, and scientific) in which Minolta had made scant little inroads at the time.

Minolta engineers used a costly tricks to get acceptable colour pictures in 1.75 mega-pixel resolution:

1 - Relay optics reduce the image size from Minolta's normal 35mm SLR lenses from 36 x 24mm to 16 x 12 mm, about 1/2 or ~0.5x, (doubling the effective focal length) and reducing the e widest effective aperture to f/6.7.

2 - The light which got through the lens was split using a dichroic prism block split the image-making light into the required components for each sensor. Each part was projected onto its own CCD light-sensor.

3 - They used two green sensors, and one red/blue combination sensor, which was striped using a microscopic filter elements. This made the camera back huge compared to film SLRs. Each CCD has a resolution of 768 x 494 pixels on 6.4 x 4.8 mm chips (~3.6% area, or ~19% linear of the size of 35mm film).

4 - Then the three images were digitally integrated and interpolated out to 1,528 x 1,146 pixels, ~1.5x. The resulting 1.75 megapixel images were stored on a PCMCIA type III hard disk card.

The handling of the camera was almost like that of other autofocus SLR cameras of the time, and the lenses for this camera were simply the same as the ones for Minolta's Alpha/Dynax/Maxxum film SLR camera bodies. The picture quality, once praised, is far behind that of Konica Minolta's later digital SLRs using Sony's single-chip 6 mega-pixel resolution.

Links

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