Reported by dpreview.com yesterday, Nikon has patented a “Color separation device of solid-state image sensor”, or what I’ll refer to as a true-color sensor for its salient property of avoiding the resolution-degrading interpolation of a color filter array (Bayer matrix).
Nikon’s patent for a true-color sensor
(Derived from USPTO application 7,138,663)
It remains to be seen if Nikon can actually manufacture such a chip cost-effectively, and with a high pixel count. It might never see the light of day (patents are also competitive weapons), or Nikon might be poised to announce a breakthrough camera which could shake up both the high-end digital SLR and medium format digital back market. Presumably Canon has some competing technology, but the digital imaging patent wars could just be heating up—this kind of technology will be highly disruptive when it emerges.
Foveon already manufactures its “X3” true-color chip and indeed incorporates it into its SD14 SLR. The results are impressive, with color and spatial resolution demonstrably superior to cameras with up to twice the megapixels (I haven’t used it personally, but I’ve examined various samples). The problem with the SD14 is its relatively low resolution, and the requirement to use Sigma lenses. It’s also not a pro-level body, like a Nikon D2x or Canon EOS 1D. In short, a non-starter for pros.
A true-color sensor derives red, green and blue values at each “pixel”, as compared with a color filter array, which can record only red or green or blue at each location—hence the need for interpolation, which degrades image quality. A true-color sensor records 3X the information for each “pixel”. Therefore, a 10-megapixel true-color sensor would have 30-million values to record, versus 10 million for a conventional sensor. Big files, big quality.
A true-color sensor might be the ideal scenario, even superior to a monochrome sensor in some ways. While it would be unlikely to offer the same low noise and dynamic range as a monochrome sensor, the availability of the red/green/blue values offers compelling post-shoot flexibility when converting a color image to a monochrome one, or for infrared false-color, etc.