How do higher resolution sensors affect apparent noise, all other things being equal?
My thinking is as follows:
A percent increase in sensor resolution causes each pixel to decrease in size by the same percentage.
This decrease in pixel size would reduce the maximum number of photons that could be held by each pixel (presumedly by the percent increase in sensor resolution), thereby reducing dynamic range and SNR. However, resolution increases while SNR decreases, so the apparent noise remains constant as resolution decreases (if the picture is viewed at an appropriate viewing distance).
Specifically, I am interested in the tradeoff between the D600 and D800.