With no mirror, the autofocus system used by the Panasonic G10 (and other Micro Four Thirds models) works in a slightly different way to DSLRs. It uses the image sensor to analyse image sharpness, rather than using a separate 'phase detection' sensor. But although this is generally slower, this fact of physics did not make itself particularly noticeable in our tests.
The basic 14-42mm lens (with an equivalent angle of view to an old-fashioned 28-85mm zoom), does not stretch the autofocus to the limit, of course, in the way that a telephoto zoom lens might. But all the same, it worked well.
There is a good range of focus options, even without the touch-control option that you'll find on the G2. Face focusing on the G10 works well – and manual focusing is greatly aided by the electronic viewfinder, which zooms in automatically to allow precision adjustment of the lens. In auto mode, it gives excellent feedback as to which of the 23 AF zones it is currently able to render in sharp focus.