College Graduation Advice

In a month or so I will be photographing my brother in law at his college graduation. He's the grad speaker, so I'll have at least 5 minutes to get him on the dais. My plan is to bring my XT, 17-85, sigma 10-20 (for whole stage shots - he'll be up there the whole time), and rent a 70-200 IS and maybe another lens.

The graduation is outside, so light shouldn't be a problem in availability, only in direction (potentially). For position, I'll be sitting fairly close, in the VIP section (I don't know the layout though, so that could be quite variable)

I was planning on taking some shots of the Dean and checking the graph to set exposure ahead of time.

Does anyone have any other graduation advice? I would love to rent an 85 1.2L, but I'm not sure I will be close enough to be useful. The 135L also sound fun, but I'm not sure if 2.0 will be that much different from 2.8, as I will already have that focal length covered. How about a flash? I know from my trip to Madagascar that a flash would have come in very handy for fill during the day in the jungle, but would it be worth it in an open college campus? I'm dying for an excuse to get a 580EX (I or II), but I don't know if this would be it.

Thanks for everyone's help.

Red

The answer is simple. Buy the flash. If you understand fill flash and 'how-to', then you'll have better shots. Especially if there is a back-lit situation. It is a once-in-a-lifetime occasion.
The 70-200 is a good choice.
Don't forget to get the "over the shoulder" shot of the BIL speaking to the audience.

I know if it was me I'd leave the camera home because my 'great seats' would put their backs to me for everything.....

I really like the 70-200/2.8. It should work just great if you are within reasonable distance.

Thanks for the advice Jon. Do you have an example of the "over the shoulder" shot you are referring to? I'll only be able to shoot from head on, since I'll be a spectator.

Seems to me you'll need more info on the layout. Will there be a covering for the speakers or will they be under direct sunlight, time of day counts too!

"I would love to rent an 85 1.2L, but I'm not sure I will be close enough to be useful. "

Sounds like, you'll be using the 70-200 the most.

Last friday was my sons graduation. The ceremony was indoors and we were near the back of the hall. Canon 70-200 F4L @ 200mm @ F4 & ISO 800 (on a 350D (Rebel XT)) and a 580EX did the trick for wait to head shots (with a little bit of cropping). Beware of red eye. The 17-85 IS lens was ok for the before & after shots outside. A F2.8 lens would have alowed some natural light shots inside.