Let's face it, people are by far the most popular photographic subjects, and they all have faces. Shooting a frame-filling close-up of a toddler eating spaghetti doesn't pose much of a technical problem for the autofocus(AF) and auto-exposure(AE) systems of today's digital cameras: they'll focus on her face and give you a perfect exposure.
But when you place that toddler's face off center near the edge of the frame, compose a double portrait of mom and dad, or photograph a group of people sitting around the dinner table, things start to get interesting. Conventional AF systems will sometimes miss the faces and focus on something else that may be farther away or closer. The result: The people in your picture will be out of focus, blurry and over- or underexposed—not a good thing.
Fortunately, a number of leading camera manufacturers have addressed this sticky problem (ahem) head-on and have come up with ingenious solutions known as Face-Recognition, Face-Detection or Face-Priority modes. Basically they are all a form of pattern recognition: when you turn on the camera's face-detection system, the AF and AE systems analyze the objects in the frame, detect face patterns (up to 10 in some cases), focus sharply on intended subjects, and adjust the exposure so they are properly exposed.
These systems can't perform miracles, of course, such as achieving a sharp, perfectly exposed image of Uncle Fred who is 27 feet away and Aunt Martha whose face is 3 feet from the camera. But they do a remarkably good job over 90 percent of the time, and they do it automatically.
The only thing you have to remember is to turn on the face-recognition system when you're taking people pictures and not to select it when shooting, say, scenic vistas.
The Face of the Present—and Future
Face recognition is just the latest example of how advanced technology can help people take better pictures automatically without having to think about how the camera works. It's the hot new digital point-and-shoot feature of 2007, and it's clear that major camera manufacturers think it's very important.
Cameras that incorporate face-recognition technologies are available from Canon, Fujifilm, Nikon, Panasonic, Kodak, Pentax, Samsung and Sony. Some outstanding recent examples: the Canon PowerShot SD1000 Digital Elph, the Fuji FinePix F40fd, the Pentax Optio A30, the Nikon Coolpix P5000, Kodak Z812 IS, and the Samsung NV11.
Face Detection has also recently turned up in some advanced cameras including the 10.1-megapixel Panasonic LUMIX DMC-L10 proving this feature, like optical image stabilization, has legs and you'll see it in more and more cameras going forward.