QUOTE (BernardLanguillier @ Jul 22 2009, 11:20 PM)

One question though, the larger the amount of pixels in a given surface, the smaller the photo-receptive surface, right (assuming that we are already pretty optimized there)?
Aren't we going to run into another wall which is the amount of photons hitting the photo-receptive surface during a short exposure? Since light is essentially a discrete quantity, the amount of photons is in fact directly related to the amount of steps that can be discretized, and therefore essentially to the bit depth, correct?
I think there are two aspects of this problem. One is that all pixel boundaries will loose photons so when you increase resolution you will at one point have a sensor that only consists of pixel boundaries and no more is able to record any light. The other is that higher resolution sensors will have to cope with the same number of photons but will be able to record their position more accurately. This is of no use any more though when the pixels are so small that a significant number of them does not receive any photons at all (and the usefulness of the additional pixels rapidly decreases with photon count per pixel approaching zero).
But of course there are many situations where sufficient light is available to still decrease pixel sizes quite a lot. This would mean lower sensitivity sensors of course.
Greetings,
Christoph