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This may change the face of digital photography!

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Sigma's Foveon Sensor: What It Is and How It Makes Megapixels Obsolete
June 3, 2011 -By Sebastian Anthony

Sigma's Foveon Sensor: What It Is and How It Makes Megapixels Obsolete - Technology News by ExtremeTech

In the next few days, Sigma will release the SD1, its first foray into the realm of professional digital SLR photography. With an ostentatious street price of around $7,000 (and an MSRP of $9,700!), the SD1 is priced above both Canon and Nikon's flagship 1D and D3 cameras, yet feature-wise it is similarly matched against the 5D and D300, which retail for only $2000. Buyers of the SD1 won't be new photographers, either: they'll be professionals with a bag full of lenses, none of which will fit the Sigma body. So why is Sigma charging almost $10,000 for a new and unproven camera? How is the SD1 different -- or better -- than a Canon or Nikon that can be had for a quarter of the price? It's all about the sensor.

Beneath the SD1's rather mundane exterior lies a brand new 46-megapixel Foveon X3 direct image sensor. Unlike the standard CMOS image sensor found in every other DSLR camera, the Foveon X3 has (you guessed it) three layers of photon-sensitive silicon. In conventional CMOS sensors, there is just one layer of silicon that is divided up, using a Bayer filter, into red, green, and blue receptors. Light passes through these filters, the luminance is recorded, and then the camera's software turns the data into an RGB image. With the Foveon sensor, there are three layers of photo-sensitive silicon, each made up of 15 million receptors, and each one only receptive to one color. For more details, or if you're having a tough time visualizing how it works, check out the demo that compares X3 to standard single-layer CCDs.