Panning the Camera
Panning the Camera
The technique is called "panning the camera". What you want to do is pan (move from left to right or vice versa) at the same speed as your subject. This captures the body of the car as static and the wheels and background as moving. The trick here is consistency. Try not to move the camera up and down, otherwise everything is blurry. If in doubt use a tripod.
If you move the camera too fast (left to right) - the body of the car will be too blurred. It takes alot of practice. At the 2004 Montreal Grand Prix, I shot 8 rolls and had a 70%-75% hit rate. Not bad, but an expensive way to shoot. Plus I didn't know till I got the pics developed if any turned out. I've since swithced to digital.
As for shutter speed/ISO/Aperture (the holy trinity)
Use a fast(ish) film, like ISO400. If you are shooting in bright daylight, you can get away with something slower (100 or 200) but I found 400 really versatile. And if the waether goes balmy you've got a fast, low grain, film.
Shutter speed: don't got too fast, you don't want to stop the action completely - then it looks like you took a picture of a stationary car. No fun. You want a sense of speed and movement. I'd usually shoot 1/250th or 1/350 sec. Click the picture right before or as the car enters the viewfinder. The old adage, if its in the viewfinder, its too late. Of course this depends on how fast the car is moving.
Aperture: don't shoot with big apertures(small f/stop number, like f4). There is not enough depth of field and focusing will be tricky. The sweet spot for any lens is f8. This is ideal becasue you don't care about background detail, you're trying to blur it out.
A manual camera will add another dimension to this experiment - depending on how fast your subject (highway or racetrack?) you won't be able to maintain focus fast enough. If your camera has autofocus, it may be able to track the car as it goes by you and maintain focus. Otherwise pick the spot at which you want to capture the shot and prefocus at some point where you think the car will be.
What kind of camera do you have? Can it shoot multiple frames a second? That would make life easier. Try a google search of "motorsports photography" & "technique". I recall seeing a number of other forums that I got advice from a few years ago. Sorry I don't have the sites bookmarked.
I'd attach some of my pics but I don't have them on a public server anywhere. If you want I can email them.
Best of luck.
