Many still photographers get started in video with a “hybrid” camera. Canon just came out with the EOS 7D to add to their already popular EOS 5D Mark II. Nikon has their – D90 and Panasonic has the Lumix DMC-GH1K.
There is plenty of information online particular to all of these cameras so rather than repeat what others have written, I’ll list some tips on shooting with these cameras.
1. Don’t shoot verticals when in the video mode – the reason should be obvious but nevertheless because these cameras look and feel like still cameras (and are) turning the camera vertically is a common mistake photographers make.
2. Use an external mic if audio is important and it usually is.
3. Use a tripod – hand holding video is far different than hand holding a still camera where just the “moment” has to be sharp.
4. Don’t try to be sneaky in venues that prohibit video by pretending to shoot just stills. It’s just not ethical.
5. Remember when shooting video it’s a motion medium – so seek out subjects with motion.
6. Make sure your sensor and lenses are always spotless – while you can retouch video it’s quite labor intensive or can be.
7. Editing files from some of these cameras can be slow and clunky in the edit room, especially when trying to blend with other video shot at a different frame rate like 24p. If you’re shooting with the 5D which shoots in 30p you may want to convert your files to the standard Apple Pro Res at 24p to make everything compatible first.
8. If you’ve been hired to shoot stills for a client and they ask you to “just” shoot some video footage for them from the same camera – don’t just throw that content in for free. There’s added value there and you’ll short change yourself as well as set a bad precedent for your future video clips.
To be honest, I don’t own a “hybrid” and most of these tips have been collected by hearing complaints and advice from others. So please add your own tips and cautions.
Journeys of a Hybrid 
My hybrid, the Nikon D5000, shoots good-looking, high-def video. Sound quality for music stinks, however. There is no connection for an external microphone, and I believe that’s true for most hybrids. Aloha.
Although I have two other video cameras (an XH A1 and an HV-30), I feel much more adept with the 5D because the form factor is so familiar. I feel like I’m composing a video instead of being stumble fingered with the video cameras that I don’t have years of experience on. The footage looks so good out of it that I’m thinking of selling the video cameras and relying only on the 5D. I just got a Zacuto finder for it, and it has made a huge difference in thinking of my hybrid camera as a real video camera. I can precisely focus it now, which is more than I can say for the video cameras.