shooting a conference -- advice for a first timer?

hey! this is my first post, although i've been reading the forums for awhile. i'm an amateur photographer who volunteered on short notice to shoot a reasonably large conference of two large student-run anti-poverty groups at MIT, starting tomorrow. i'm not being paid, but it's a serious event (the first speaker is john edwards) with 1500ish people, and i have never photographed anything in any sort of professional capacity. does anyone have any advice? the most important shots i'll be responsible for are posed group shots, which i have very little experience with.

i have a canon 20d, 430ex flash, and sigma 18-50mm f2.8 -- i might rent a 70-200mm telephoto tomorrow morning if it seems necessary.

although i'm not the only photographer they've got, the rest are also all students, and from what i've been told it seems like i might be the most experienced person they have---so while the expectations are not necessarily very high, i need to be as on top of things as i can be. anyway, i'd really appreciate any advice you guys can give me!

keithcc wrote in post #5349691
hey! this is my first post, although i've been reading the forums for awhile. i'm an amateur photographer who volunteered on short notice to shoot a reasonably large conference of two large student-run anti-poverty groups at MIT, starting tomorrow. i'm not being paid, but it's a serious event (the first speaker is john edwards) with 1500ish people, and i have never photographed anything in any sort of professional capacity. does anyone have any advice? the most important shots i'll be responsible for are posed group shots, which i have very little experience with.

i have a canon 20d, 430ex flash, and sigma 18-50mm f2.8 -- i might rent a 70-200mm telephoto tomorrow morning if it seems necessary.

although i'm not the only photographer they've got, the rest are also all students, and from what i've been told it seems like i might be the most experienced person they have---so while the expectations are not necessarily very high, i need to be as on top of things as i can be. anyway, i'd really appreciate any advice you guys can give me!

If you're shooting John Edwards then you'll definitely need the BS filter (#102) since he's both a lawyer and a politician Seriously, I'd definitely rent or borrow a telephoto of some kind. The 70-200mm would be perfect.