Panning—following a moving subject by pivoting the camera while the shutter is open—has two big benefits for shooting wildlife. It captures the subject sharply, while streaking the background to show motion. It can also help you keep your subject sharp when the lighting’s too dim for you to set faster, action-freezing shutter speeds. Panning typically requires the shutter to be open for 1/8 sec or longer, depending on subject speed. Whether you’re handholding or using a tripod (which can produce straight, parallel lines in the background streaks—a cool effect), start the pan before the shutter is open and keep moving until after it’s closed. Like most things in life, practice makes panning perfect.
(From 5 Nature Shooting Skills April 2009 issue)