Shooting night football games is a challenge, let alone doing sports photography is a challenge all together, then you add the lighting variables. Yikes!!! But it is fun and when you can get good shots, you win!! I've been asked, "So, how do you shoot night football."
Yes, I do use the BIG white L lens...currently just the 70-200mm IS f/2.8 and planning on getting the 300 IS f/2.8 when profits flow. My camera is a 40D and I'm loving it next to the Mark DIII that I can't have right now. However, if you do not have the right lens, you can rent them.....I use Borrowlenses.com....ask for Max. He's great!!
During the football game, from the start to the finish, I'm constantly changing my settings...of course, as the game progresses it gets darker...
At the start of the game, I use Shutter Priority, usually an iso of 400-800, shutter speed of 1/500 or lower[for the games in August/September, I go faster like 1/5000 why not, its bright enough].... f/4.0 - f/2.8. I do not use an extender for night games due to loss of the aperature...f/2.8 is needed hands down. Continuous shooting, AI Servo, center focus point....as the night progresses, I begin cranking up the iso [usually by halftime I'm at iso 3200], and start locking the aperature at f/2.8...so by then I typically switch between Aperature Priority or Program Auto Exposure. I have yet to attempt manual mode :)
And you are right, I do not use flash....I only have my built in or my 580EX and personally flash makes the photo look too fake IMO. I have seen nice ways of using external flashes, but right now, I don't want to add that to my bag. Instead, I move around the field [I'm on the sidelines right next to the coaches and players] and try to get the stadium light behind me, and I play around with my exposure compensation [ currently at 1/3 increments, but still playing around with what increments will work best] by increasing it...on my camera this little trick will not work in Manual Mode.
My lens has image stabilization....I do not use a monopod....too restrictive to get the cool shots and lessens my mobility. I will only use the monopod when its cold like in the teens and snowing because then my whole body is shaking and with that much shaking going on, the IS can't handle it. My coldest game was 10C and snow in West Virginia, proud to say however, that I was last photographer standing on the sidelines....
Also all my photos are taken in JPEG...I know shoot me now...I use RAW for my portraits, but with sports, I need speed and RAW just slows up the process. Plus, I typically take 1500+ photos per game. my 40D captures at 6.5 frames per sec and I need that. Also, I use a card with a write speed of 300x...this helps too. 133X will work as well,,,,don't use a an 80X just too slow for continuous shooting.
I use auto white balance, but making adjustments using White Balance shifting focusing on the visiting team's usually white jerseys....again very subtle shifting and sometimes not at all.
My post processing involves a batch processing through Noiseware, very subtle to minimize the high iso noise [the 40D does have built in noise reduction for high iso, which does great when your exposure is just right].....fix the levels, curves, color as needed, crop, then subtle unsharp masking (if needed). If the face is too dark and that is the emphasis, I paint light on their face - just a little trick that I like to use. And once in a while, I'll do my photoshop magic taking the image out of the ordinary :)
So in a nutshell, get a zoom lens of at least 200mm, 300mm is better, 400mm is great, 500-600mm is best, an aperature of f/2.8 or less, fast shutter speed until it gets dark, crank up the iso, continuous shooting centered focus.
Have fun... Go Steelers!!!
Seasoned Pros are welcome to provide their comments and tidbits too!!!!