Some of the coolest stuff comes in pairs: salt and pepper, cats and dogs, Abbott and Costello, rhythm and blues, thunder and lightning. When it comes to cameras, we have the essential pair of aperture and shutter.
Last week, I talked about how you can use your digital camera's aperture priority control to move beyond the automatic setting and get creative. This week I'll focus on the shutter priority mode.
Shutter Priority: What Good Is It?
When you get right down to it, the camera's aperture and shutter do essentially the same thing: They regulate the amount of light reaching the sensor to record a picture. If you have a wide-open aperture, the shutter will open for a relatively short time. But close the aperture to admit less light, and to properly expose the photo you'll have to lengthen the time that the shutter is open.
However, the aperature and shutter controls affect a photo very differently in other ways. On one hand, your choice of aperture determines a photo's depth of field. The shutter, on the other hand, makes a photo sharp or blurry, depending upon how long it's open.
Selecting Shutter Priority
Most digital cameras (except for inexpensive auto-only models) have a shutter priority shooting mode. To get to it, select the "S." On some cameras, especially Canon models, shutter priority is represented by the letters "Tv." Either way, once you select this setting, you can freely choose the shutter speed and the camera will set the matching aperture to properly expose the photo.
Getting Good Results With Shutter Priority
What's the right shutter speed to choose for a given situation? Your main concern, at least in the beginning, should be using a shutter speed that's high enough to eliminate any shakiness caused by holding the camera. In normal daylight--assuming that you have fairly steady hands--consider 1/30 second the slowest acceptable speed unless you brace the camera somehow. If you have a handy wall, door frame, or tree to rest against, you might get good results at 1/15 second.
And those numbers are when you're zoomed out, with the lens set at a wide angle or "normal" focal length. If your camera has a beefy lens 3X zoom (or more), you might need to shoot a lot faster to freeze the action. In the world of 35mm film cameras, we used a rule of thumb that said you should shoot at a shutter speed that's the inverse of the focal length. So if you have a 200mm lens, get as close to 1/200 second as you can (that's usually about 1/250 second). With a 50mm lens, you'd get as close to 1/50 second as you could, and so forth. That rule still holds true--so if you have a digital camera with a zoom lens that reaches 200mm or more (in 35mm equivalent), then crank up the shutter speed accordingly.
Follow these basics and you'll get sharp photos with the camera set to shutter priority. Once you master that skill, you're ready to try your hand at action photography, where the shutter priority mode really excels.
Taking Great Action Shots
There are two kinds of action shots. The most common, frequently seen in sports photography, uses the highest shutter speed available to freeze the action. Alternately, you can go for a slower shutter speed and let the resulting blur tell the story for you: Nothing says "this thing was really zipping by!" like a blurry background.
Freeze the action: Even in bright daylight, you might want to increase the camera's ISO setting in order to get a very high shutter speed, which will help you to freeze a fast-moving subject.
What's a fast shutter speed? If you're at a car race, an air show, or a sporting event with lots of fast action, then I recommend 1/1000 second or faster. (Many digital cameras can reach 1/8000 second.) In fact, no shutter speed is too fast if it allows you to get a shot that you wouldn't be able to get otherwise. For example, this shot of kids playing soccer was taken with a shutter speed of 1/1600 second.
Get some blur: To blur the background, try setting a shutter speed of 1/15 or 1/30 second, then follow the action by pivoting your body to track the subject. Press the shutter release and keep moving. With practice, the subject will freeze and the background will be a smooth, dramatic blur, like this.