To take pictures, you will need a spotter with you.
There is no entry fee to spectate. Just sign the waiver.
If you ARE going to take pics, please find the safety steward that is on duty (ask the people wearing the vests in grid, they'll have a radio) and then ask them if it's OK to go out on course... bring your own spotter. You need to have someone with you at all times to watch your back.
And when you ask the guys in grid, please do it after a change in run groups, not when there are cars on course. They have enough going on to keep a busy event running safe, and with 250 cars, things have to run like clock work.
Bring a good telephoto if you're planning on going out on course... you'll be asked to be about 75' off course... but if you didn't ask a safety steward 1st before you go out on course, you'll be asked to leave when they find you.
So to recap...
1) Bring someone with you as a spotter. No spotter, no pictures
2) Find the safety steward for the run group and ask if you can go out nd where its safe to do so.
3) Bring telephoto lens because you won't be any closer than 75 feet.