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Meter Reading False Friends

By Mike Pasini, Editor
Imaging Resource Newsletter

The big smile, the firm handshake, the hearty laugh and ... the deed to that swampland in Florida. False friends. What would we do without them? Life just wouldn't be as much fun.

"One friend that is never false is your LCD monitor. Trust it in tough situations to give you reliable, if limited, feedback."

It's hard to detect them, of course, because false friends always inspire the most trust in us. Like your exposure meter. Why wouldn't you trust it?

Well, your camera's meter has its moments of riotous humor, too. Not many, but a few. Being aware of them will help you avoid some routinely poor exposures. Like those dark beach scenes you get every summer.

Your meter is calculating the correct lens opening and shutter speed to expose for a middle gray or 18 percent reflectance. A predominantly white scene will be underexposed to turn that whiteness into middle gray. Likewise a dark scene will be overexposed to make the darkness turn gray instead of black.

Whether or not you have manual control of your lens aperture and shutter speed, you can compensate for these false readings. On an automatic camera, you'll have to adjust the EV or exposure value compensation settings. But that does the job.

Sunlit snow or water will bedevil the camera's meter. If you're shooting scenes with these tricksters taking up most of the frame, don't trust your meter alone. Instead, open up your lens two stops or increase your EV to +2.0. Your meter is reading too much light for the shot.

If the subject is sand, sky, or shady snow, open up a stop or increase your EV to +1.0.

Those adjustments assume the frame is filled with tricky reflected light. But if it's only half the frame, your meter reading will be only partly off, so you'll want to make less than the full adjustment. And if you mix and match (hard to avoid on the beach where you have sand and sun on the water), pick a value between the two.

If your subject is giving a false reading simply from too much sky in the picture (on a grassy field, for example), aim your camera down a bit to eliminate the sky from the shot and press your shutter button halfway down to lock the exposure before reframing and taking the shot.

"Your camera's meter has its moments of riotous humor, too. Not many, but a few."

When the scene confuses the meter, you can use your hand to help out. A light-skinned palm reflects about one stop more light than an 18-percent gray card. Meter your hand and close down a stop, or set your EV to -1.0.

If you follow this advice, you'll be having so much success you'll never want to go home, which means at the end of the day you'll be wondering how to shoot the sunset.

This is one case in which metering the sky is a good idea. But avoid metering the setting sun itself. Instead, pan either to the right or left of the sun to take your reading (that's north or south to you intrepid adventurers). Pick the side that most looks like what you want to shoot, of course. And try to shade your lens from the sun with your free hand. Then just set the exposure with a half-depressed shutter button and reframe for the shot.

One friend that is never false is your LCD monitor. Trust it in tough situations to give you reliable, if limited, feedback. The color may not render truly (especially compared to the phosphors on your computer monitor or the dyes in your printer) but the brightness range should be telling. You may have to learn just how telling, but your LCD should give you valuable feedback.

As the saying goes, a friend in need is a friend indeed.

This article is reprinted from The Imaging Resource Digital Photography Newsletter,
Advanced Mode Column, published July 28, 2000