Photographing a fast-moving subject like a race car or a runner or a bicyclist in the Tour de France? If you use a fast shutter speed as you’re “supposed” to do, you’ll freeze the subject and make them perfectly sharp. They can look, actually, like they’re sitting still. Instead, you can use a horizontal panning motion with a slow enough shutter speed to add blur to the scene. By moving the camera from one side to the other, moving it with the traveling subject, you’ll keep the subject sharp, or at least moderately so, and the fast-moving parts of the subject, as well as the background, will be blurred. The amount of blur depends on the shutter speed, and that relies largely on what look you’re trying to achieve. A really fast subject might have plenty of background blur by panning at a 1/125th shutter speed, while a slower-moving subject might require a quarter-second pan or even more. The reverse of this technique also works; hold the camera still and let the moving subject become a blur as it streaks through the otherwise static scene. Which approach you take depends largely on the story you’re trying to tell. Is the photo about the place? If so, the latter approach with a blurry subject may be preferable. If it’s intended to tell the story of the moving subject, however, a traditional pan with a blurry background and sharp subject is likely ideal.
Artful Subject Blur
Are you telling the story of a dancer and her beautiful spinning movements? Then you might consider the deliberate and artful use of motion blur. By letting her spin her dress and twist and turn with a slow shutter speed, you can instill the feeling of movement and show literally how the subject moves by photographing the evidence of her movement—the motion blur. Even if most detail is lost, the blur may still be an effective storytelling tool. It doesn’t take much in the case of, say, a spinning wheel or a flowing dress, so you might start your shutter speed experiments around 1/30th of a second and adjust faster or slower based on the evidence you see on your camera’s LCD. With a subject just standing there in a steady pose, you might need a 1/4 second exposure to register any notable blur. Don’t hesitate to try it; sometimes just a bit of blur can do wonders for a straightforward portrait. Even if it’s really blurry, as long as the feeling is right you’ve done your job. That’s what makes it artful, after all.
Dragging The Shutter
Want to do something really special with your motion blur? Add a bit of flash. The combination of sharpening flash and blurred ambient offers really the best of both worlds. You get the motion feeling from the blur, yet the flash freezes the subject in place for one brief moment, giving the viewer something sharp and clear to gravitate toward in the middle of all that motion blur. When you use a slow shutter speed of, say, 1/30th of a second with a flash exposure to photograph a person—even a person who’s attempting to stand still—you’re likely to record a bit of their motion via the ambient exposure, even while the flash exposes what’s primarily more important—the sharp subject. Try it with a subject that’s moving and you’ll get some amazing special effects—like a motorcycle or skateboarder with a shadowy motion blur behind them or a simple thoughtful portrait with an outline of subtle blur. If you really want to get funky with it, you can deliberately pan your camera or zoom your lens during the ambient exposure. This will further enhance the ambient motion blur while again relying on the strobe exposure for a sharp subject.