The first stage I was at had very little light, I had ISO 400 and with the 70-200 f2.8 could only go to 1/200 2.8 but alot of them are around 1/100 or that way.
Its the sigma version I have alright on a Nikon D50. Its a very good lens. I have only used one other one the canon 70-200L IS f2.8 and it was on a 30d so was better but I dont think worth the money for the improvement. The Sigma has very fast focus and is sharp. I dont use it at f2.8 much, mainly f11 or higher on good days. I like slower shutter speeds, but it was the first time I had no choice. I think they look different, most of the rally photos look like the car is parked.