Compared to the image quality of digital still cameras, which measures in the millions of pixels, the image quality of digital camcorders seems pathetic. Most consumer-level units contain a single CCD (charge-coupled device) that captures approximately 290,000 pixels. But note that camcorders record interlaced video, which means that in any given frame, only every other horizontal line is recorded. (Broadcast television uses a similar method.)
Many current camcorders can take still pictures and save them to another media, usually a CompactFlash card or Sony's Memory Stick. The advantage of this approach is that more image data is captured, using a noninterlaced process called progressive scan display. Some camcorders offer this still-picture feature without being able to save to a separate media, which ends up being useless; the image is saved to the MiniDV tape by freezing it and recording it for five seconds (the audio continues to record, however, so you can often hear people talking even though they're frozen on screen). Personally, I'd rather use a digital still camera for taking photos and save the camcorder for what it does best: video capture.
One of the limitations I've found with my Canon ZR20 is that the built-in microphone is mounted above the tape's motor, so when I'm shooting in quiet situations, the microphone picks up the sound of the motor. In most cases this hasn't been a problem, but if you're looking to remake My Dinner With Andre, you may want to compensate by using an external microphone, such as a lavalier (clip-on) type or a directional mic that attaches to the top of the camera. Any decent camcorder will have a port into which you can plug a microphone.
As a testament to how deeply I was sucked in by the flexibility and freedom of shooting digital video and editing it in iMovie, I wrote a book about it: iMovie 2 for Macintosh: Visual QuickStart Guide. Now that I've introduced you to the world of DV camcorders, let me share some shooting and iMovie tips I picked up while writing the book.
This article originally appeared in slightly different form on the TidBITS Web site, where Jeff Carlson is Managing Editor.