Isn't there a kind of noise that gets overproportionally worse when pixels get smaller? Otherwise it is strange that sensors optimized for low noise often have a low resolution. I am thinking about that sensor by Canon for example that can do images with ISO 3,276,800 or so and only has a very low resolution. Of course if noise is random at each pixel, you can average it out, but there also is noise with other frequencies that effects a hundred or so pixels in the same way, Averaging it out will not work there and it could get worse on small pixel, because on small pixels tha signal has to be amplified much more than on a large pixel.
Upvote
0