The green channel has the least noise for Bayer-sensor digital cameras (which is almost all of them).
50% of the sensor sites are green (25% each for red and blue), so there is more signal given the same amount of noise.
50% of the sensor sites are green (25% each for red and blue), so there is more signal given the same amount of noise.
The Foveon sensor does sample RGB at every pixel by using 3 layers, but it is only used in a few cameras.