I always get people asking me if I shoot video on my Canon 5d Mark II , and people are always surprised when I say . . . Super Rarely/ No. I'm not a director, I'm a photographer. I'm comfortable saying that and most people should be too. If your not, and think simply getting the camera is all it takes, this video is a splash of cold water. [vimeo http://vimeo.com/18104656]
Here is the video he's speaking of in case you missed this excitement about 2years ago
Here is the Behind the Scenes Helicopter Capture
Here is an image that shows what you would need to do it right (thanks to DSLRvideorigs blog). Uh . . . Like another $10,000.00 worth of gear, easy.
Here is a great resource if you are still crazy enough to want to do this: http://www.cinema5d.com