Conversely, moiré patterns can be understood as a result of high spatial frequencies being folded to lower frequencies due to insufficient band limiting (provid

Conversely, moiré patterns can be understood as a result of high spatial frequencies being folded to lower frequencies due to insufficient band limiting (provided by an optical low pass filter in front of the image sensor) and thus violating Shannon's principle. This isn't an accident, we simply prefer sharper images that possibly contain spatial aliasing over less sharp (i.e. less high frequency content) images that never contain spatial aliasing. The reason why moiré patterns are generally colourful is because each pixel is not sampled at a point, but with the colors distributed over some area. Hence each color component of a pixel sees a slightly phase shifted component of the signal, i.e. it gets rainbowy. You would expect the moiré exhibited by a planar sensor like the Foveon X3 to show this effect to a lesser degree.