The Bayer filter was patented in 1976 and can be found in almost all digital camera sensors sold today.
While several alternatives have been suggested over the years, some more exciting than others, none caught on. This could soon change, though, as Canon Watch reports that the 120MP full frame sensor Canon is developing will not be based on Bayer technology.
After initially reporting that the sensor will be based on completely new sensor technology, CW’s trusted source clarified that the sensor may be “a technology similar to Foveon”.
The reason for Canon choosing to go with new sensor technology, according to the source, is that Canon says the RGB sensor (Bayer filter) doesn’t work as well for resolutions higher than 100MP.
A Bayer filter mosaic is, as described by Wikipedia, “a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camcorders, and scanners to create a color image. The filter pattern is 50% green, 25% red and 25% blue, hence is also called RGBG, GRGB, or RGGB”.
Source: Wikipedia
The Foveon technology (now owned by Sigma), on the other hand, uses photosites consisting of three vertically stacked photodiodes rather than placing the color filters side-by-side.
Source: Foveon.com
This means that demosaicing is not required and each photosite creates its own RGB output, rather than being assigned information from neighboring photosites.
As such, Foveon sensors do not require AA filters, do not suffer from the color artifacts seen on standard sensors (CMOS or CCD), and have better light gathering capabilities.
While the Foveon technology is not problem-free, it seems that business relationships and money (and some technical issues) were the main reasons why it didn’t catch on, not technological inaptness.
Assuming this information is true, the question is did Sigma finally manage to significantly capitalize on the technology it acquired back in 2008 or did Canon come up with its own technology, similar enough to enjoy the same benefits but different enough not to infringe on any patents?
Either way, Foveon or Foveon-like, the 120MP camera just got a whole lot more intriguing!
[via Canon Watch]
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