hi...
im not a canon shooter so not too sure of the setting names... i would start with shutter prioirty, as touring cars are fast i would start with 320th sec shutter speed and mess around with diff speeds... ideally there should be some wheel blur to show the speed...
i would set to center metereing so the car is well exposed, to start off center point focus so the camea focuses on the car and not the tree in the background! set your camera to continious auto focus and set to burst mode. for panning / side on shots i try to keep around f8 so play with the ISO to alter the f.
head on shots you could increase the shutter speed say 500th sec, and open up the apature so f4.5 as you dont need the wheel blur as much as you cant really see the wheels! [unless its an open wheels car with treaded tyres then you need some blur of the tyres!]
for panning twist from the hips and keep very smooth, as you have a long lens i would hold my left hand on the very end of the lens / lens hood keeps it more stable.
watch where the sun is as can cause lots of glare! just over your shoulder behind you works for me...
you could also set the camera to sport mode and let the camera work it all out for you, my mate does this with his 1000d and gets good shots! cheating a bit! :0 you will loose control over the shutter speed and the photo a little, but very good for learning...
and just ask any tog if you get stuck.. chances are there off TP and sure people will be more than happy to help
hope this helps a little
bob
