Action! Capturing motion with shutter speed
Have you ever wondered why still photography is thriving even though it's so easy to capture video with our smartphones. I’d say it's because there’s something endearing in the knowledge that a photo has captured a moment in time. Still photographs depict a slice of some action, and you can convey that action in a lot of different ways. Let’s take a look at how to freeze action with your digital camera.
Role of shutter speed
If you’re really interested in experimenting with action photos—whether it’s sports, cars, or even just your dog romping around the yard—you should have a camera in which you can dial in the shutter speed yourself rather than relying on an automatic setting or an “action” scene mode. The Shutter Priority mode works well; this lets you select the shutter speed, and the camera picks the right aperture to deliver the right exposure. Many cameras also have a Program mode, in which the camera appears to select aperture and shutter automatically. But by using a dial or arrows on the camera, you can shift the shutter speed to be faster or slower, and the camera adjusts the aperture—almost exactly like the Shutter Priority mode.
Why is the shutter speed so important? That’s easy: This setting determines how long the sensor is exposed to light. A fast shutter speed tends to freeze the action, while a slower shutter is more likely to cause blur.
If you find yourself with a camera in hand at some sort of action-oriented event, it’s hard to go wrong with a fast shutter speed. The faster your shutter, the more likely you’ll be able to freeze the action. A fast shutter helps you in two ways: Not only does it freeze the action, but it minimizes the effect of a camera shake, which happens if you’re hand-holding the camera without the support of a tripod.
If your goal is to freeze the action, you’ll generally want to shoot with the fastest shutter speed that your camera will allow. 1/1000 second is good; 1/40000 second is better. Want to know the bare minimum that’s acceptable? The shutter speed should be at least the reciprocal of the focal length to minimize camera shake. So if you have a 200mm lens in your camera, make sure the shutter speed is at least 1/200 second. If you have trouble making the shutter speed fast enough, increase the ISO. Of course, the usual caveat applies: Faster ISOs result in digital noise.
If the fastest possible shutter speed freezes the action, then you can guess what a slower shutter speed can do—it’ll introduce blur into the scene. This can be a really effective technique to convey a sense of motion or action. After all, a perfectly frozen subject doesn’t necessarily look speedy. But shoot the same scene with a shutter set to 1/15 second, for example, and the subject will whiz through the photo like blurry lightning.
What’s fun about this kind of photo is that there’s no one right way to shoot this. Experiment with different shutter speeds and check out the result in the LCD display. Of course, when you slow down the shutter speed, you should try to mount the camera on a tripod to steady the overall scene. If everything is blurry from camera shake, the photo simply won’t make any sense.
My favorite technique for capturing motion in a photo is to shoot with a slower shutter speed and, instead of keeping the camera still so the subject zooms through the scene, pan the camera to keep up with the subject. When done well, the subject will be fairly sharp, and it’s the background that’ll blur—conveying a powerful and dramatic sense of motion.
The trick to this technique is to start tracking the subject as it comes into the scene and smoothly pivot your body to keep it centered in the viewfinder. As it passes directly in front of you, gently press the shutter release (don’t jab or stab it) and continue to follow through, pivoting to track the subject even though you can’t see it as the viewfinder went black. You’ll need to find a shutter speed that works well for you, but I recommend starting around 1/15 second.