So this gets into wave vs photon theory with light, but just pointing out 715 nanometers is 0.715 um and the pixel dimensions of the 1DX III are 6.58 um x 6.58 um, assuming gapless configuration (not a bad assumption with the microlenses). I do not know the depth of pixel "bucket", but my point is that we are not actually that far off in the size of pixels from the wavelengths of light. I could see some interference for longer wavelengths such as IR. This isn't even getting into wave amplitude, which in a quick search I didn't find.