>>>Not sure I agree. The red filter throws away all non-red light.
Well not exactly all. Canyon uses a less dense Colored filtered array
(CFA) than some
to gain better high ISO performance at the cost of possible less color
discrimination. They actually admitted this briefly on their site and
quickly pulled the comment for the 5DII. Sony (especially) and Nykon
seem to have denser CFA and this manifest as higher SMI: (Sensitivity
Metamerism Index) as reported by DXO.
http://www.dxomark.com/index.php/About/In-depth-measurements/Measurements/Color-sensitivity
some scores:
Sony a900: 87
Sony a99: 85
Sony Nex-6: 85
Nikon d3x: 79
Nikon d800: 78
Canon 5D: 84
Canon 5D3: 74
M9: 76
A thinner CFA will still result in chroma noise increase you get from
increased color processing to yield good results, so their is no free
lunch.
As I understand it the SMI is a rather complex metric that does not
tell the whole story---
A camera with an SMI of 80 can be WORSE than a camera with an SMI of
75, if the errors are in sensitive colors and if they are incorrigible.
But a camera with SMI 80 will almost certainly be a lot better than the
camera with SMI 60
I have not figured out how noise-covariance step integration works and
other items but the cams also do
complex spot color corrections to improve performace in this area as
well.
What this new technique does to color separation/accuracy, DR etc
remains to be seen. There may be unforeseen complications as happened
to Fuji's new CFA as many years of software development/trouble
shooting/optimization are thrown out the window for a novel approach.
Mike
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