humbleteleskop said:
Yes, I am aware of that and I agree. What I don't agree with is when they say "dimmer" that they actually mean "smaller". Here is why:
http://en.wikipedia.org/wiki/Apparent_brightness
Is "apparent brightness" about differences in size or color brightness?
Yes, humbleteleskop, they do, we do, everybody does. Usually that's what it means for a faraway star to be dimmer - it's just smaller.
The disc of a star sends photons towards your detector(eye, ccd, whatever). The less photons reach it, the dimmer the star appears. There are various processes that could obstruct photons on their way(like scattering, absorption by interstellar dust; there could be redshifting making them less energetic, and leading to failure to trigger the detector), and make the resulting image dimmer, but the inverse square law is specifically, and only, about the geometric reduction of the area of the stellar disc. Stars two times farther away are four times dimmer exactly, and only, because their apparent discs are four times smaller.
The end result on the side of the detector is just less photons impinging on it, so as far as it is concerned, there's no difference between calling the source four times smaller and four times dimmer - there will be the same amount of photons hitting it in both cases. But the physical reason for the dimming remains the reducion in apparent size, and the distinction becomes important once you deal with objects that are larger than the maximum resolution of the detector.
In other words, you can use the point source approximation in many cases, but you need to keep in mind the real reason for the dimming, so as to know when the approximation doesn't apply anymore.
I couldn't think of how to formulate it at the time, but what I meant to ask really is this: if we set camera parameters so that we get almost completely dark photo of Olbers' paradox night sky, then a few bright spots on it would be images of the closest stars. But you seem to say it would be all or nothing, that is it would be uniform regardless of how dark or bright the resulting photo is. To me it makes more sense that photons from the closest stars would have higher chance to hit the camera in sufficient number to make an impression than photons from further away stars.
The flux of photons would be constant over the whole sky, so it wouldn't matter how far a star is(as long as all the stars have the same surface luminosity). The time needed to travel from the star wouldn't matter, as the universe is supposed to be eternal. None would stand out.
