I only have 1 year experience shooting indoor sports with a 50D and 70-200 f2.8 IS, but I can assure you that f4 is too slow. You'll rarely find an arena or indoor gymnasium with identical lighting. (Due to this, I recommend not deciding on a lense after a single game.)


So indoors I shoot: f2.8, ISO 1600, shutter speed depends on the lighting, game and age of player.(younger kids move slowly, teenagers can move very fast)


If you can photograph from the sidelines try the 50mm f1.8, and shoot half court. The lens is cheap and will give you some settings to work with before deciding on a more expensive investment.