Quote Originally Posted by canoli
Generally speaking should AF be able to resolve as much detail as MF?

With the standard APS-C viewfinder screen and a calibrated system, I think that the f/5.6 autofocus sensors are a little more accurate than I can do with manual focus through the viewfinder. But the center f/2.8 AF sensors are definitely better than anyone can do with the standard screen.


If you use a high precision screen, MF can get close to the accuracy of a calibrated f/2.8 AF system at f/2.8, but personally I think the latter is still a little better. If you have an f/2 or faster lens, then I find MF becomes better than even the f/2.8 AF sensor, doubly so if coupled with a true ground glass or split prism viewfinder (e.g. Katzeye).


Liveview beats them all, of course, for subjects that are slow enough to use it.


Quote Originally Posted by canoli
I'm getting more resolution by focusing manually.

Your body and/or lens may be slightly out of tolerance at the zoom and focus distance you are using. If you had microadjustment (e.g. 50D upgrade), you might get sharper results. My 70-200 and 50mm f/1.4 lenses both required micro-adjustment.