I currently shoot with a digital rebel and the only time where I can use al servo is when I am shooting in sports mode. To me this is a little annoying. I like to be able to have more control over my ISO and aperture but that is lost with its sports mode. I am wondering if on the 10D and 20D you can use al servo in more costomizable situations. If so, what are they and how is it costomizable? Can you just turn on and off al servo, or is the sports mode more customizable? If so, to what extent?