I may have the opportunity, to take a picuture of every student being handed their diploma at an evening graduation ceremony outdoors. Around 250 students in the senior class. Here is the layout of the situation and I would appreciate your input. Ceremony is on the football field, starts at 8, still have decent light but when the ceremony rolls around, it will be dusk or dark. The stadium is modern so the lights are good for sports, not sure how good for this. FYI--I have shot many good football action photos with out flash, using the high iso capabilities of my 7d, and I always shoot raw. Basically I don't want to slow down the ceremony, and it will be discussed on how much of a turn and pause to look at the camera will be allowed. My equipment--I shoot with a Canon 7D, have some fast glass: 70-200 IS 2.8, 85 1.8, 50 1.8, kit lens 17-55. I do have the canon 580 flash. My thoughts / concerns I have a tripod, and can set up where I need to get a nice composition of the student and school board pres handing the diploma no time to change batteries if 250 shots won't last completely I suppose I can get some type of battery booster to wear on my side, not sure what they call it I am assuming the largest print that parents would want to buy would be an 8 x 10 I know I don't want to compose to tightly I would like to use the 70-200 if I can work that lens into the set up and be far enough back Off camera flash is not really an option, unless you feel it is absolutely necessary I was considering shooting in Aperture priority, see what f stop gives me a fast enough shutter speed. I know the tripod will help here. My flash synch speed is 200. Certainly red eye is a concern with my on cameral 580 flash, due have a diffuser. Do to my success on that field taking sports pics without flash, I would like to be able to continue with out flash, if possible. Anyway, I would appreciate any suggestions and input regarding lens choices, things I need to be aware of, etc etc. I need to pull this off flawlessly.