HD pocket camcorders: What's the catch?
- — 30 April, 2009 01:59
Pocket camcorders are great for convenience, but their HD video performance definitely suffers
Not all HD footage is created equal. High-definition 'pocket' camcorders make compromises in video quality so as to shrink the cameras' cost and size. (Examples include the Creative Vado HD, Pure Digital Flip UltraHD and Kodak ZI8). While their small size makes them convenient, it's important to be mindful of their considerable limitations. Here's a rundown of the cons that might burn a hole in your pocket.
Lower-quality lenses: Tiny, simple lenses grab less light and provide less light control than lenses on bigger HD camcorders.
Tiny imaging chips: Light gathered by the lens hits a single, tiny (typically 1/4.5-inch) CMOS chip that packs many photosite sensors into a small area. Bigger HD camcorders usually have bigger and/or multiple imaging chips. On pocket HD camcorders, fewer photons hit each photosite sensor, resulting in compromised images in low-light situations and other tricky conditions.
Fewer pixels: Pocket HD camcorders typically generate 1280x720 pixel images. Full-size HD models can capture 1920-by-1080-pixel footage, and those higher-resolution source images generate better final images, even when delivered at lower resolutions.
Weaker image processing: Bigger camcorders are built with intricate image-processing systems to control colors, reduce noise, and improve image quality under varying lighting conditions. The image processors in pocket HD camcorders, on the other hand, come with much more limited processing power.
More (and coarser) compression: Creating great-looking video with the H.264 codec requires more processing and a higher bit rate than minicamcorders can provide; most pocketable models compress video at about a 9-MBps bit rate. Larger HD camcorders use AVCHD compression (also a form of H.264), which provides better, lighter compression. Their bit rates (and file sizes) can be two to three times those of pocket HD camcorders.
Tough shooting conditions: The more complex the scene, the greater the difference in image quality between pocketable and full-size HD camcorders. Pocket models struggle to create good video in conditions of low light, high contrast, and fast or extensive motion (including motion that is introduced by unsteady hands).
When recording a well-lit scene without too much contrast or movement, however, pocket HD camcorders can generate decent video. See our HD Pocket Camcorder Roundup for more information.
