Single-sensor cameras reduce chroma twice: the Bayer CFA measures R or B on only 25% of sites, then 4:2:2 or 4:2:0 throws away reconstructed Cb/Cr. Native red or blue sample density matches 4:2:0, not 4:2:2. Pairs with
PhysLight,
CIE 1931,
Bit Depth, and
Resample Filter Lab.