Digital Focus: Capturing Subjects on the Move
Whenever I talk to people who have recently made the switch from film to digital photography, I always seem to hear the same complaint: it's hard to stop the action. Whether it's a toddler darting across the living room or a race car speeding around a race track, new digital photographers seem to get a lot of blurry shots or, even worse, nothing at all. The subject is long gone by the time the camera takes the picture. The culprit? Shutter lag, and I can tell you how to get rid of it.
Hmm. Perhaps that's being a bit overoptimistic. I can't promise to eliminate shutter lag, although I can give you a few strategies for minimizing it. But first, what is shutter lag?
Shutter lag is the name that we've given to the seemingly interminable wait between the time you press the shutter release and when the picture is actually taken. All cameras--film or digital--have some sort of shutter lag. On digital cameras, though, it can be uncomfortably long. When you press the shutter release, the camera has to focus the lens, measure the white balance (so the colors look right in the final image), and do a host of internal housekeeping duties, like preparing the sensor to capture an image.
Preset the White Balance
The first thing you can do to minimize shutter lag is to set your camera's white balance control to one of its preset values, like daylight, indoor, sunset, or whatever other settings is appropriate for the situation. If the camera doesn't have to measure and calculate it manually, you just saved some time. It's not much--a few hundredths of a second--but it can mean a lot when the action is fast.
For more on working with your camera's white balance control, read "Fix Your White Balance."
Set the Focus Before You Need It
The other big time saver is to lock in your focus before you need to take the photo. You might already know that if you apply slight pressure to your camera's shutter release, the camera locks the focus. As long as you hold the button down lightly, the focus will stay locked. To take the picture with that focus setting, just press down the rest of the way.
This is an important technique to use to shorten your shutter lag, since it can take some cameras about a half second to focus. So if you're trying to catch a photo of someone darting around in front of you, lock the focus and keep tracking the action. At the right moment, finish pressing the shutter and you'll get a much more immediate reaction from your camera.
Tweak the ISO
Even with those other precautions, sometimes you still can't get the photo you want. Your subject might be front and center in the scene, but due to poor lighting, the shutter speed is so slow that everything is a blur. The fix? Find your camera's ISO control and increase it a couple of steps. ISO measures your camera's sensitivity to light, and so shooting at ISO 400 instead of ISO 100 means that you can possibly catch a photo at 1/60 second instead of 1/15 second. That's the difference between being able to read the letters on a player's jersey and just recording a blur.
Of course, remember to reset the ISO to its lowest setting when you're done, because higher ISO levels add digital noise to your photos. But if I have to choose between a blurry photo and a few speckles of unwanted color in the frame, I'll take the noise.
For more advice, read "Use ISO to Take Low-Light Photos."
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