There's always been all this talk about full frame sensors and how they're the best because they're larger. They have more dynamic range, less noise, yada yada. And the full frame supporters always point to two reasons for this... the size of the pixels and the density of the pixels.
Ok, I gotta call BULL S^!T.
This might have been true, once upon a time. But look at the numbers now. The Canon Rebel XT's pixels are 6.4. The Canon 5DmkII pixels are 6.4. The pixels density is also similar on both cameras. Yet the 5DmkII produces better quality images with less noise and has a higher ISO range than my trusty Rebel XT.
I think it's not as much a matter of pixel size, as it is a matter of overall sensor quality. Because really, when we take away the question of size what else is left to say that these cameras are better? It's certainly not the other features, since the 7D out specs the 5DmkII in many areas.
There are other differences when it comes to full frame vs. crop. but when it comes to overall image quality, how does size figure in these days? If they can get the higher ISO performance with less noise when having pixel density and size similar to a Rebel XT... then make a comparable crop camera. Yeah, it will have less MP than it's full frame counterparts. So why don't they leave that for why you'd get the full frame version? Don't stiff us on the ISO and noise, because if you look at the size it's clear they can apply the technology now and make a lower MP crop camera with the same great performance.
I don't know, and I'm a little ranty this morning. But I think that photographers need to stop buying into the notion that size matters. Have no shame when you shoot with that crop camera. Because really, in the end it's not what you've got but how you use it that matters anyway.