The important thing in resolution is the number of red-green-blue pixels sets, the pixel-set resolution. High-end digital video cameras have 3 CCDs. This enables them to capture a complete set of red-green-blue pixels for every pixel in the rated resolution. Digital cameras using the Foveon chip, such as the Sigma SD9, also capture a complete set of red-green-blue pixels for every pixel of rated resolution. So the number of red-green-blue pixel sets is equal to the megapixel rating. The megapixel rating and megapixel-set resolution are identical.
Most digital cameras and low-end digital video cameras have a single CCD to record all three color channels. This is accomplished by dividing the CCD into four pixel blocks one of which records red, two of which record green and one of which records blue. So, number of pixel sets is actually one forth of the megapixel rating given these chips. The megapixel rating is four times the megapixel-set resolution. So, you should divide the megapixel rating for these chips by four when comparing to 3 CCD or Foveon-based systems.
This explains why digital video looks so good when it is converted into 35mm motion pictures for commercial release in theaters. The digital video is shot on a 3 CCD camera. So, even though the image is only .37 megapixels, the megapixel-set resolution is also .37 megapixels. It would take a 1.5 megapixel single CCD image to produce the same megapixel-set resolution.
While Canon sold Foveon to Sigma a while back resulting in the newer Sigma models (SD9 - maybe) having foveon sensors they have patented their own three layer sensor in a similar design to the foveon. Possibly resulting in the inclusion in this camera so in reality you would have a single 6MP sensor with three layers. (maybe).
Aug 28, 2009 at 08:41 PM
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