My tip is to use ~ 1/300ish if doing a side on shot, any faster and you'll freeze the wheels which makes it look like it's parked on the track (I didn't follow this advice myself and regret it). If the car is front on you can use whatever speed you like.
My other tip is experiment with panning (eg down around 1/100) and I really like the look of a panned wide angle lens shot if you are close.
My other tip is to use AF-C, even with a K-x I found I got far more keepers in AF-C mode than AF-S.
My last tip is to avoid debris fences, or if you can't, get real close to the fence and shoot as wider aperture as you can.
this photo I failed the debris fence test as well as the shutter speed test
I did a slightly better job here but not much, I still needed to get closer to the fence
Unfortunately F1 now is not like I remember in the 90's when I attended quite a few races, no debris fences to be seen and the cockpits were cut low so you could see more of the driver.
Last edited by twitch; 05-16-2011 at 11:53 PM.