400mm lens for motorsport. which one?

VisionLight wrote:

It's been my experience that for anything other then small court sports, if you're only going to have one camera and one lens, then bring a zoom. In motorsports especially since the "court" is so large. It's an expensive lens I know, but I've never been dissapointed by my 100-400L on full frame. On your camera it would be a 160-640, so think about how often you're going to be trackside when the short end may be too long. With crop cameras the 70-200L would be 112-320 and the 75-300 would be 120-480. Possibly in your case a little more versatile. There are also different versions of both of these lenses at different price points.