• Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint


Any camera must be set to allow just the right amount of light in order to get a properly exposed picture. Fortunately, digital cameras are very smart and do this automatically. But there are some situations that call for your input to make a photo come out the way that you want it to.

Many cameras give you the ability to set shutter speed (the length of the exposure) and aperture (how much light is let in for the exposure) manually.

What Does Autoexposure Do?

Autoexposure gauges the proper amount of light required to get a good shot. As with autofocus, autoexposure will do the job in most situations; but there are some situations where it won't properly gauge the correct exposure. Autoexposure, like autofocus, uses the center of the frame to measure the light. So if there is a particularly bright or dark area near the center of the frame, it will throw the exposure off.

To compensate, temporarily move the camera so that the area with the amount of light that you want is in the center of the frame, and hold the shutter button halfway down. Then reframe the shot, and press the button all the way to take the picture (Figure 4.7).

Figure 4.7. The sun behind the trees caused the autoexposure to underexpose this shot (left). Aiming the center of the viewfinder at the ground and holding the shutter button halfway down caused the autoexposure to use the darker area to set the exposure (right).

Setting Shutter Priority

Some cameras let you manually set the shutter speed while having the autoexposure set the appropriate aperture automatically. You can use this Shutter Priority option if you're trying to capture a subject in motion and you want to either freeze the motion (with a faster shutter) or blur it (with a slower shutter) (Figure 4.8).

Figure 4.8. With a fast shutter speed, the motion of Sarah on the mower is frozen. With a slower shutter speed, the mower looks like it's going at a much faster clip.

Setting Aperture Priority

Aperture Priority works much the same as Shutter Priority, except that you set the f-stop and the camera then chooses the right shutter speed. This can be useful if you want to increase the depth of field. Because aperture on most digital cameras doesn't have as noticeable an effect on depth of field as with a larger camera, this is not a feature you're likely to use much.

Using Manual Exposure

For the adventurous or advanced photographer, some cameras offer a manual exposure option. You can set both the shutter speed and the aperture yourself. You'll have to gauge the proper exposure on your own. You can try taking several shots at different settings and reviewing each shot on the camera's display to figure out the optimum setting (Figure 4.9).

Figure 4.9. Three different manual exposures on the same subject show more and less light. Shoot it several different ways, and you can then choose the one that work best.

Setting Exposure Compensation

If you want to use the autoexposure but still want a degree of control, some cameras offer exposure compensation. With this feature, you can set the autoexposure to be slightly lighter or darker to tone down glare in very bright sunlight or to enhance highlights in deep shade.

Most exposure compensation controls measure the compensation as positive and negative decimal numbers. Setting a positive number will make the picture brighter and a negative number will make it darker (Figure 4.10).

Figure 4.10. The first shot of Dan's lawn tractor was set with a positive exposure compensation setting, creating a brighter shot. The middle shot was set with no exposure compensation. The last shot was taken with a negative exposure compensation setting, resulting in a darker image.

Setting White Balance

If you're shooting in certain kinds of lighting, such as indoors with artificial light, you can wind up with odd-looking results. Because artificial light has different amounts of color than natural light, a shot may wind up looking too red or too green. (See “Correcting Color Shifts” in Chapter 9.) Digital cameras have a marvelous feature called white balance that will correct this kind of problem before it happens. By setting the camera to automatically correct for different types of light as you shoot, you can get a good-looking photograph without having to do extensive color correction in your image-editing software.

White balance can be set to correct for:

  • Incandescent light

  • Fluorescent light

  • Cloudy outdoor light

  • Bright outdoor light (full sunshine)

Most cameras also have an automatic setting that will determine the best white balance setting (Figure 4.11). But there are no set rules about white balance. Every camera handles it a bit differently, so a bit of experimentation will give you a sense of what works best.

Figure 4.11. The default white balance setting on most cameras is Auto.

If you're using a flash to shoot, you may not have to worry about color correction—the flash will provide properly balanced light. But if the flash will only cover the subject, the background may still show a color imbalance. So in that case you'd use the white balance.

  • Creative Edge
  • Create BookmarkCreate Bookmark
  • Create Note or TagCreate Note or Tag
  • PrintPrint