David Pogue's Digital Photography: The Missing Manual

White Balance: Manual or Auto?

Most people new to photography have never even heard of white balance. And the truth is, not many people fiddle with this setting, especially among pocket cam owners.

Anyway, here's the deal: It might freak you out to find out that your brain is constantly playing tricks on you, and color casts are a case in point. Fluorescent lighting is slightly bluish; traditional incandescent indoor lights are a bit yellow; snowy scenes are often bluish, too. But the weird thing is that it doesn't look that way when you're there! Your brain instantly adapts to these lighting casts, making the lighting seem normal.

Cameras, as you've probably learned by now, are brainless. So those varying color temperatures, as they're called, affect your finished photos. From "coolest" (most blue) to "warmest" (most red), the common lighting conditions that produce color casts are candlelight, tungsten (incandescent) bulbs, sunrise/sunset, fluorescent bulbs, camera flash, bright and sunny, daylight with overcast skies, and, finally, outdoors in the shade.

In the days of film, you'd have to correct these color casts by installing a tinted filter on your lens. On a digital camera, though, life's a lot easier: The sensor can do the correcting.

It's supposed to do that automatically, in fact—and generally does, which is why so few people muddle with white balance. Still, there are two reasons why you might want to set the white-balance mode manually:

• Because the camera is not doing a good ...