I just bought my son a mini bike for his bday. Well I am all excited to shoot in manual but when I go to adjust my shutter speed it won't go over 1/200 all of a sudden??? I was on manual mode all day yesterday and had no problems. Even when I change the ap I still can't get over 1/200? I really want to get some shots of him before the sun goes down. My camera is the canon xsi. Does anyone know what is causing this?