Take advantage of face detection

We love photographing people. But our cameras aren’t always cooperative. They focus on the bricks in the background instead of on handsome Uncle Ted, or they set off a blinding flash that washes out playful party pictures. This sad situation hasn’t gone unnoticed by the engineers who design digital cameras—which is why many of the newer cameras on the market include a new technology called face detection.

With this mode turned on, your camera locates the people in a shot and then fine-tunes the focus and exposure for those faces. While this may sound like a superficial gimmick, I’ve found that it works surprisingly well—it can greatly increase your chances of getting good shots at a wedding or family reunion. But even if your current camera doesn’t offer face detection, you can become a better photographer by embracing its concepts. Once you understand how face detection works, you can enable many of the same features on practically any camera.

The secrets of face detection

If you have a new compact camera, take a peek at its specifications to see if it offers a face-detection setting. Typically, this option is in a camera’s autofocus (AF) menu. Face detection is particularly handy for candid shots, when you’re working quickly and are therefore more vulnerable to misfocused shots. It’s also a boon for flash photography. With face detection turned on, the flash doesn’t try to illuminate the whole room, just the people within range—cutting down on the nuclear blast effect.

Using Face Detection: With face detection turned on, the camera highlights faces on the LCD screen and then sets the focus and exposure for the subject.

Using the face-detection feature is fairly simple. As you compose your shot, your camera highlights the faces on the LCD screen and then gives you the green light to shoot. If the camera isn’t finding the person in your shot, the problem may be that it can’t see enough of his or her face. Face detection is much more effective when the camera can see both eyes of the subject; its accuracy diminishes greatly with profile shots. Also keep in mind that although face detection is fast, it isn’t instantaneous. For best results, compose your scene and then press the shutter button down halfway to activate face detection—this will give the camera time to adjust its settings appropriately. Once the camera shows that it has identified the subjects in your composition, press the shutter button down the rest of the way to make a perfect exposure.

Face detection is so simple that you may be tempted to leave it on all the time. But as with any setting, it’s not right for every situation. When photographing sporting events and landscapes, for example, you’ll probably get better results by switching to one of your camera’s other focusing settings. I recommend reserving face detection for family gatherings, weddings, and other people-oriented events.

DIY face detection

Although face-detection technology makes photographing people easier, you can get similar results without it. The trick is knowing how to adjust your camera’s settings to emulate what face detection does.

Proper Focus You tried to get a shot of Aunt Jane having an animated conversation with Uncle Ted, but your camera focused on the fireplace between them instead. That’s because your camera likes distinctive lines, especially when they appear in the center of the frame. With face detection turned on, your camera is able to detect Aunt Jane and focus on her—not the columns of bricks behind her. If you don’t have face detection, you can better control your camera’s focus by following a few simple steps.

For starters, switch to single-shot AF. This setting is usually found in a camera’s AF menu. Point the camera directly at the person you want to focus on so that he or she is in the middle of the frame, press the shutter button down halfway to lock in the focus, and then recompose the shot and press the shutter button the rest of the way. Photographers have been using this tried-and-true method (called focus locking) for years.

The problem with focus locking is that you can miss a good expression while you’re recomposing the shot. If you’re in good lighting and don’t need a flash, you can partially compensate for this by enabling your camera’s burst mode (sometimes labeled as Continuous in the drive-options menu and depicted as a stack of photos). Start by turning off the flash. If your subject isn’t in direct sunlight, make sure the ISO is set to 200 or 400 to better handle lighting and then switch to burst mode. Now lock the focus as before, but this time keep the shutter button pressed down to take a series of shots. Your odds of getting a natural expression will increase dramatically. (Unfortunately, this rapid-fire mode won’t work in dim settings, where you need to turn the flash on. Flashes often take a few seconds to recycle, which means that a flash will go off only every fourth or fifth frame in burst mode.)

Better Flash Exposures Shooting with the flash on most compact cameras can be challenging. The built-in flash tends to overexpose people, making them look as though they’re being interrogated under a floodlight. The beauty of face detection is that the camera knows what part of the image you care about and tries to adjust the flash for the correct exposure. But even cameras that don’t offer face detection often have other modes that are helpful in these situations.

First, check your camera’s scene modes for settings that might help. Many cameras include presets such as Party, Indoor, Night Snapshot, and others that are designed to help you get interesting portraits with your flash—even in challenging lighting conditions. When you pick a scene mode, your camera gets a better idea of what you’re trying to do. For example, if you pick the Party mode, the camera knows that you want good people pictures and that you aren’t out in the wilderness shooting rocks.

If your flash still overexposes your subjects, find its flash compensation setting. This usually looks like a scale that goes in this sequence: -2, -1, 0, +1, and +2. Try setting the scale to -1. This tells the camera that no matter how much light it thinks it should use for a picture, it should use a little less. Picture still too bright? Then try -2.

Some cameras also include a nifty Flash Exposure Lock (FE Lock) feature. This lets you tell the camera what the most important aspect of the scene is and then provides just enough flash to illuminate it. To use FE Lock, make sure your flash is on, and then focus on the subject that is most important to you and press the shutter button down halfway. While still holding down the shutter button, press the FE Lock button (usually it’s nearby). The flash will send off a test firing to set the proper exposure. Once it does, press the shutter button down the rest of the way for the final exposure. You should get much better results.

[Derrick Story is the author of The Digital Photography Companion (O’Reilly Media, 2008). His weekly photography podcast is available on iTunes.]

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