Originally Posted by ftpaddict 
Who says they won't? Focusing is lens-independent, for the most part.
Contrast-based focusing can work with any AF lens. (just don't ask the 4/3 camp; they'll say it isn't true
)
In theory yes.
But for the 4/3 micro system they claim that one reason for the speed advantage with their contrast AF over other makers contrast AF is because of the lenses being especially designed for fast re-checks of autofocus. Lenses not up to the task will be manual focus.
They choosed this solution instead of having a slow system, like Canon and Nikon's current implementation of contrast AF for their LiveView cameras.