When you are photographing a fast-moving subject, the most important setting to be aware of is your shutter speed. If the shutter speed is fast enough to freeze your subject, then you should see little or no motion blur. If your shutter speed is too slow, your subject will end up being a colorful streak across the frame.
Shutter speed is measured in fractions of a second, so when you are reading the numbers on the top LCD Panel or in the viewfinder, look for a very high number for a fast shutter speed. Even though you are shooting in fractions, the camera won’t actually show shutter speeds that way but instead will display whole numbers. There’s no single setting you can stick with to be sure you will freeze the action—the shutter speed you use will depend on the subject you are photographing and how fast they are moving. Also keep in mind what direction the subject is traveling and how far away you are from them. Let’s take a brief look at each of these factors to see how they might affect your shooting.
DIRECTION OF TRAVEL
When determining exposure for action photography, the first thing you might think about is how fast the subject is moving, but in reality your first consideration should be the direction in which it is traveling. The speed of something moving from left to right is perceived differently from that of something moving toward you. With the subject moving left to right, you’ll need to set your camera to a faster shutter speed to freeze them in place, since using a shutter speed that is too slow could blur your subject. With a subject moving toward the camera, you can get away with a slower shutter speed, because they appear more stationary (Figure 6.1). A subject that is moving in a diagonal direction—both across the frame and toward or away from you—requires a shutter speed in between the two.
Once you’ve determined the direction your subject is heading, you’ll need to assess the speed at which it is moving. The faster your subject is moving, the faster your shutter speed needs to be in order to “freeze” the action (Figure 6.2). A person walking on a sidewalk is moving quite slowly, so you will be able to use a slower shutter speed, such as 1/60 of a second, in order to photograph him or her with little or no motion blur. Using the same shutter speed to photograph a speeding car would result in the car being blurred across your image, so to compensate, you would need to use a much faster shutter speed.
One final factor to keep in mind when photographing moving subjects is their distance from you and your camera. Imagine that you are standing on top of a tall building looking down at the street below. You can watch the cars moving with little effort; in other words, your eyes don’t have to move very far to see cars travel from one block to another, and you don’t have to turn your head much to follow them. Now put yourself on the sidewalk directly next to the street, and try to follow those cars traveling the same speed—you need to move your head from left to right to keep your eyes on one car. Standing on the street requires a lot more movement on your part to keep up with the moving traffic.
Now imagine you are holding your camera and trying to photograph the cars in both of the above scenarios. Although the subject is traveling at the same speed in both instances, the movement of your camera will affect the shutter speed you’ll need to use in order to freeze the action. Photographing a fast-moving subject that is farther from you requires a slower shutter speed than if you were standing a few feet away from it, because the perceived speed is much slower.
This same principle can also be applied to the lens you use. If you are using a wideangle lens, you can probably get away with a slower shutter speed, whereas using a telephoto lens brings you in closer to the subject and will require a faster shutter speed to compensate for the movement of the lens following your subject (Figure 6.3).