so the boy is in a rememberance day parade on sunday and i want to get some good shots of him. What kind of setting should i have it on? The perfectionist side of me wants a nice candid head shot of him with the background blurred out but they will obviously be moving so do i really need to have it on shutter priority. any idea of what settings i should have it on?

i'm thinking i should use my 70-300mm f4.5-5.6 lens as i don't want to be intrusive lol.

any tips gratefully recieved:p015: