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| Video-Mode Standout: Canon PowerShot S3 IS |
“A riddle wrapped in a mystery inside an enigma.” Winston Churchill wasn't talking about digital video, but his phrase applies. Even more so now that you can use your digital camera to shoot movies. The jumble of video-related acronyms and numbers on still-camera feature lists can be hard to make sense of, and you might well wonder whether the video results you'll get from a still camera make it worth the trouble of decoding the lingo.
Fortunately, these days they often do. You can get higher video quality and a broader range of controls if you're willing to spend more than a few hundred dollars on a camcorder, but the video that some digital still cameras produce now rivals that of lower-end digital camcorders.
However, there are significant differences in the quality and capabilities various models offer. Understanding what all the specs mean and knowing which features matter can make the difference between watching tiny, jerky, 30-second clips and viewing natural-looking videos with stereo sound that fill your TV or computer screen and last as long as the event they capture.
Breaking the Code
There are four basic elements to consider when it comes to video: frame size (resolution), shape (aspect ratio), speed (frame rate), and sound.
RESOLUTION: As with photos, a video's resolution affects its quality and the size at which it can be displayed. But the resolution you need for a good-looking image on a TV or monitor is much lower than what you need to make a decent 4x6-inch print. Video resolutions in still cameras (and most camcorders) are well under 1 megapixel. They're described in terms of the number of horizontal by vertical pixels captured: A 640x480 video frame is 640 pixels wide and 480 pixels high.
Problem is, video resolution is also described by acronyms that correspond to specific resolutions. For example, that video with 640x480 pixels per frame is called VGA resolution. Knowing what the acronyms stand for can be confusing (we've listed the full names on the next page to satisfy your curiosity). But the important thing to know is which acronym corresponds to which resolution, and what image size you need for the type of display you'll use.
ASPECT RATIO: Video comes in different shapes -- witness the evolution of TVs in the past few years. While nearly all cameras record video with the 4:3 aspect ratio of a standard television screen, some models now offer 16:9 widescreen capture. Most cameras achieve this by masking strips at the top and bottom of their 4:3 sensors, but Panasonic has models with true 16:9 sensors, so they don't lose resolution in widescreen mode. These 1280x720- and 848x480-pixel-per-frame videos will be more at home on a widescreen TV. Some cameras that capture 16:9 stills record only 4:3 video, so check the specs carefully.
FRAME RATE: Described in terms of the number of image frames per second (fps) that the camera captures, the frame rate is crucial to the look of your video. If it's too slow, the image will flicker and action will be jerky. Soap operas and news programs in the U.S. are typically shot at a standard 29.97 fps. Movies shot on film have a frame rate of 24 fps; professional videographers often shoot video at 24 fps to help achieve a “cinematic” look. If you reduce the frame rate to about 16 fps, you'll get an effect similar to old silent movies.
Digital camcorders sold in the U.S. typically capture 29.97 fps to meet American TV standards, and many still cameras now match that performance with 30-fps capture or even top it with a supersmooth 60 fps.
It's best to opt for a camera with a top speed of 24 to 30 fps when recording 640x480 video. (Beware those that compromise resolution to achieve a higher frame rate.) You can usually select lower frame rates for special effects or to save room on your memory card.
SOUND: Don't discount the importance of good sound. People generally tolerate flaws in image quality better than poor audio -- while you might be able to pass off badly exposed, jerky video as a “style,” you're unlikely to convince your audience that noisy, tinny, uneven sound is anything but bad.
Unfortunately, the sound captured by many digital cameras isn't very good. Built-in microphones often pick up camera noises, such as the sound of the autofocus system. And some inexpensive cameras don't even capture sound with video images.
To get the best audio, look for one of the few models (from Canon, Casio, or Sony) that capture sound in stereo. Also look for a camera with a built-in wind filter, such as Canon's PowerShot S3 IS. These are standard features on most camcorders, but a rarity on still cameras. If your camera doesn't provide a wind filter, try to shield its mic from strong winds while you're shooting.
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