I have my first indoor horse show very soon and really need some advice/tips. I have a rebel xsi and will be renting the 70-200mm 2.8L non/IS lens for this shoot. Flash will most likely Not be allowed. So any tips on getting great exposure without knowing a lot about manual settings, and not using flash. There will be no artificial lighting, there is a Large open entryway and 3-4 ft clear panels along the top of the sides of the arena. I just want to know what my best shot at getting great exposure on moving horses will be in this lighting. Please any and all advice and tips GREATLY appreciated.