And the image, itself, has some problems. CMOS sensors are prone to the dreaded "jello effect." This means that in high-motion camera movement, the processor has trouble down-rezzing the image on the fly for video, and so the image is distorted. Lines that should be straight are warped and bent. For this reason, the 7D might not be the best choice for handheld or high-impact action shooting.. And while shooting at 60fps seems to lessen this effect, there can still be problems with fast pans, tilts etc.
Finally, the camera has yet to develop a truly satisfactory audio system. While Magic Lantern is hard at work creating software to allow the camera to take mixed audio sources, the current audio track is auto-leveled and inconsistent. If you want to shoot with audio, you'd better get an external recorder and slate your takes.
Still, the image quality cannot be denied. And if you're a filmmaker with only a couple grand to spend on a camera, this really is the only option to consider.
If you're used to a Beta body type (or even the Panasonic HVX-200), this camera is going to throw you for a loop. Lots of options are buried in menus, and the body style is not terribly conducive to video. Handheld shooting, zooms, and quality focus racks are extremely difficult to accomplish. While there are a few rail systems available for the camera, like those made by Redrock Micro or Zacuto, they can get to be pretty expensive--especially when compared to the relatively low cost of the camera. And they still fail to solve some of the body problems like button placement and menu accessibility. Focus assist systems can help with racking, but the focus wheel is so sensitive (due to the nature of still lenses) that it's still hard to keep the subject in focus while dollying.
The whole thing works more like a film camera than a video camera, with variable film speeds, shutter speeds, and, unique to digital vs. film, a fairly involved white-balancing process. Another headache is the camera's inability to monitor out in HD via SDI. Instead, the camera opts for a mini HDMI output, which can also be used for low-quality SD video monitoring.
