Originally posted by Ari Freund I'd like to hear an explanation why full frame is a big deal (or even desirable). As I understand it, there are two aspects to FF. The first is that the same lens on FF will give a wider field of view than on conventional digital. So? If you want a wider FOV switch to a wider angle lens, or take a step back. If not possible, then tough, but by the same token if you have a FF camera and want the narrower FOV, you'll have to change lenses or move in. They're different, but why would FF be considered better?
The second aspect is pixel density. Given that you are going to shoot the exact same scene, and both cameras have the same pixel density, the FF sensor will contain 2.25 times more pixels (assuming a crop factor of 1.5) than the conventional digital one. So you'll be able to enlarge 1.5 times more (for the same print quality). But all that means is that you want more pixels. Instead of saying "I want FF" just say "I want twice the pixels."
So what am I missing here?
there's 2 main reasons beyond fov/composition...
1. 2 stop performance gain.
2. lens resolution
the fa50mm for example, really really sucks at f1.4 on a crop body. the mtf scores are in the horrible range until f2.0, but on a full frame it'd perform much better. the catch 22 of this is as ff bodies approach the resolving limit of the glass, poor performance becomes more obvious.