I have an XTi that I'm just starting out using. When using lenses with a wide aperture in which focus becomes important I'm having some problems making sure my focus is where I want it. If I have a static subject, that's easy; I can just adjust the AF focus point. But if there is a lot of motion, for example a party, how do I make sure my focus is on for every picture? I could just focus manually, but that adds another thing to do (I'm still working on getting my exposures right). I could change the AF focus points in real time, but I don't think I could do it fast enough since the composition of the frame changes drastically from shot to shot. Any suggestions?