5D ii 2 Live View questions
You can autofocus while in liveview.
All you have to do is keep the the AF-ON button pressed until the camera achieves focus (the focus box/rectangle on the display will turn green once this happens and you'll hear the "beep" telling you that the focusing is done).
You can choose the focusing "criteria" in the menus.
There's the contrast detection focus (mirror stays up so its basically the same as MLU). Focus is done via contrast analysis. The camera makes the lens go back and forth until optimal contrast/sharpness is obtained, so you'll notice the lens searching the best focus. This maybe the most handy when using in liveview IMO. (though manual focus is always more accurate)
Then you have the quick focus - in this mode the mirror closes so the autofocus sensor can achieve focus, (so you loose liveview for a second) and then the mirror opens again and liveview comes back. (so this mode is the same autofocus you have when you aren't using liveview).
The third mode is a derivation from the contrast detection focus with the difference that it can "hunt" smiles/faces... (not really usefull IMHO).
Hope this helps.
Less is More -