Also, the screens on AF cameras only show you the D of F and brightness of f/2.8 or so. In addition to making it more difficult to focus, this also means that when shooting at apertures wider than f/2.8, you actually get less D of F than you see in the viewfinder.
Huh? Howzzat work? I agree with the brightness part, but how can a focusing screen change the apparent dof on the screen?