How to Combat Blur in Your Digital SLR Shots - dummies

By Robert Correll

Shutter speed is just like other dSLR exposure elements: It has a side effect that has nothing to do with exposure. In this case, the side effect is preventing blur. The shutter speed has to be fast enough to capture moving objects sharply, and if you are shooting hand-held, your shutter speed has to be fast enough for you to keep the camera steady during the exposure.

Blurry photos or subjects are caused by movement. Either you or your subject, possibly both, is moving enough that the light the camera sensor collects is smeared.

Camera shake, rattle, and roll

Camera shake, a form of blur that affects the entire photo fairly uniformly, is caused by motion on your part. Although long shutter speeds are a major culprit, instability in your grip or stabbing the shutter button like it’s the last button you’ll ever press also make for camera shake. There are a few ways to fix camera shake.

Faster shutter speeds

For basic hand-held photography, a good rule is to set the shutter speed at least as fast as the reciprocal of the focal length you’re using. In other words, put a 1 over the focal length you’re using to get the fractional shutter speed.

If you’re shooting with a 50mm lens, keep shutter speeds at 1/50 second or faster to counteract shake. By the same token, if you zoomed in to 100mm, you should make your shutter speed 1/100 second or faster.

Sony cameras have a camera shake warning that flashes when you’re in an automatic shooting mode and the camera sees that the shutter speed may be too low for a steady shot. Sony also has a SteadyShot scale, which is a series of bars that appear when the camera shakes. More bars indicate more shakery.


Vibration reduction (VR) or image stabilization (IS)

These features also help reduce camera shake. When you turn them on, these features may let you slow your shutter speed from one to three stops without blurring the photo. While Canon and Nikon rely on stabilization built into certain lenses, Sony dSLRs and dSLTs have SteadyShot image stabilization built into their camera bodies.

To turn on VR/IS, switch the button to On.


Mirror lockup

One source of camera shake that isn’t your fault is caused by the mirror. Digital SLR mirrors rotate up out of the way to unblock the sensor. It flips back so powerfully that it can shake the camera. This is a problem when you’re using a telephoto lens or shooting macros.

Use your camera’s mirror lockup feature (also called Mirror Up mode or Exposure Delay) to combat this type of camera shake. If your camera has a mirror lockup option, turn it on from the menu system. Putting your camera on a tripod and using mirror lockup with a timer or a remote is a sure-fire way to avoid camera shake.


Steady the camera

You have a couple options:

  • Remote shutter release: If your finger is causing the camera shake, increasing shutter speed won’t help solve the problem. Connect a remote to your camera so you can activate the shutter button without touching it. You can also switch to the self-timer and try that if you don’t have a remote.

  • Buy some legs: You should always work to steady the camera. You may use your own grip, a monopod, a tripod, or other type of rest or support. They all work.

Moving targets

You get motion blur when your subject is moving too fast for the shutter speed to freeze. The subject looks blurred. Unlike camera shake, this type of blur affects only the subject, not the background. Avoid this effect by choosing a faster shutter speed, if possible.

You can get good shots of a fast-moving subject:

  • Pan with that person as you shoot. Panning means you follow the subject with the camera as it moves across your field of view. You wind up blurring the background instead.

  • Move to another spot. It’s harder to capture a race horse moving directly across your viewfinder than one traveling towards you.

  • Try catching moving objects in moments when the action pauses, like a tennis player at the height of her backswing. Every time a moving object changes direction, you can time your shot to the moment your subject’s relative motion is smallest.

  • Pay attention to your camera’s autofocus (AF) modes. Set AF to Continuous-servo rather than Single. You may be able to select a specific AF point and place it on your target, or you may want to use zone AF if something is moving erratically. Regardless of which method you use, practice before it counts.

Focal length matters when you’re shooting moving targets, because your field of view is narrower and the subject is magnified greater than normal focal lengths. Whatever’s in your viewfinder can jiggle, jostle, and move much more than when you’re using a normal or wide-angle lens, which causes blurring. Try a higher shutter speed.

When shooting moving targets, focus will be as much of a challenge, or more, than getting the right shutter speed. Pay attention to your camera’s autofocus (AF) modes. Set AF to Continuous-servo (also called AI Servo AF) rather than Single so that you’ll be able to track a moving target.

You may be able to select a specific AF point and place it on your target, or you may want to use zone AF if something is moving erratically.

Autofocus modes, points, and capabilities are where more expensive dSLRs differentiate themselves from entry- and mid-level consumer models. The Canon 5D Mark III has no fewer than two focus modes (manual and auto), three AF modes (One-Shot AF, AI Servo AF, and AI Focus AF), six different AI Servo cases to choose from, and several AF Area Selection modes. Regardless of which method you use, practice before it counts.