the best transition is done by 3 sections at the filming stage-
firstly start with position A on character A – pan fast away from the character about 90 to 180 degrees.
(optional) secondly film a large spining shot to get that spinning motion – this is used to determin how much running time your transition needs to be
finally (this ones tricky) do a fast pan and stop abruptly on character B at position B – if it is a quick shot then it is easier to film this in reverse (i.e. start on the character and whip in opposite direction, then reverse in post- watch out for blinking eyes !!!)
put all sections together and watch the cuts – sometimes they work great depending on colour scenarios – at other times you may need to put a slight cross dissolve in.
this should give a great effect
good luck with it.
Lee.