Thanks
I have to be honest, I'm not a camera buff.. if you check out the Photography thread there are some people there that really know their stuff...
... but I'll say now, it depends on your budget, you'll pretty much need a DSLR and a couple of lenses. Personally, I've gotten this far buying mostly second hand stuff, so I'd recommend that
I'd suggest something like a 70-300mm lens for most stuff at the track. Lenses are never best when max zoomed, but something like this..
Aston Martin Vantage GT3 by
Matt Stokes, on Flickr
... was shot at 238mm with my trusty (and cheap second hand) Sigma 70-300mm 1:4-5.6 APO lens. You could go for a 200mm lens, and maybe crop the pictures a little afterwards... but, the greater the focal length, the more chance you're camera will be focusing well past any catch fences that are in your way.
In this one..
Rob Collard by
Matt Stokes, on Flickr
The reason why the rear tyre is grey, and the front one is black, is because there is a wire fence in between the camera and the car... the more you can zoom in on the car, the less you will notice the fence (larger aperture, and longer exposure will also help minimise it).
The more experienced guys will probably have better suggestions than that, but that's the way I deal with it, and I find the 300mm most suitable for this.
Beyond that, I find my cheapo 50mm prime (the F1.8 one, not the F1.4 one) very useful for not car stuff, and I've a Tamron 10-24mm wide angle that is useful for some trick shots, and when you want to fit a lot in one shot, but don't have much space..
Polestar C30 WTCC by
Matt Stokes, on Flickr
I also have a 500mm, but that was really cheap, and is therefore rubbish, so I barely use it. There's also a 28-105 in my kit bag, it's kinda useful when in the paddock for general shots, but again it was cheap, so the results are often not great.
Just my two cents