Did anyone notice that 5D3 native image resolution is exactly 1920*3 x 1280*3 (5760x3840). It is 3x3 pixel binning for video.
I've been wondering why no one has mentioned this when discussing Canon's supposedly odd 22.3MP resolution choice. This also seems to be a much overlooked factor when assessing moire and rolling shutter improvements.
The resolution certainly seems like a strange choice; it must have to do with video....
However, 1920X1080 bayer pattern (3x3 pixel binning) isn't that sharp. The F3 has a 3+ megapixel sensor and the Alexa a 4+ megapixel sensor to achieve a sharp 1080p image. In theory, bayer sensors can resolve about 70% of their stated resolution (not even taking aliasing into account)--so you need almost four megapixels to get a really crisp 1080p image. And this puts the 5DIII's 1080p mode at closer to 720p, about what the previous cameras have resolved. So that's disappointing.
The latitude, decrease in moire, decrease in skew (fingers crossed), and great looking colors still count for something, though.