Seems like being still is odd advice for performing in "moving pictures." But if you watch actors in movies, you see that the most compelling performances are generally very still. The actor's face and body movements are minimal.
Extraneous movement can distract an audience. This is not to say that you should never walk or use your hands, only that all movement should be purposeful andvisible within the screen shot.
The framing of your shot will determine the range of movement that is appropriate. When you're being filmed up close (just your head and shoulders), avoid all movement of your body. In a close up - sometimes called a 'tight' shot - any body movement outside of the frame will create shoulder movement that will seem disconnected. When more of your body is in the shot, you can move whatever is visible on camera.
Also, be careful of movement toward and away from the camera. A slight movement toward the camera can help your audience feel as if you are really connecting intimately with them. But be careful — swaying toward and away from the camera can make your audience feel uncomfortable.
Your posture communicates a great deal to your audience. Bad posture will leave a negative impression. When seated, sit up straight, knees at a forty-five degree angle, and feet planted squarely on the floor. When standing, keep your feet hip-width apart, knees soft, and head lifted. Women can choose to stand either with feet hip-width apart or in a slightly modified ballet fourth position (The front toe is pointed toward the camera. The heel of the front foot is in front of the instep of the back foot. The back foot is perpendicular to the front foot.) These stances provide you with a firm base in order to avoid unwanted movement. If you move a bit, don't go crazy with worry. Video editors can easily help gloss over any imperfections with careful editing techniques.
Stillness will help your audience connect with you and be receptive to your message. Stillness, without stiffness, will make you appear confident and trustworthy.
Laurie Brown is an international speaker, trainer and coach who works to help people improve their presentation skills. She is the author of The Teleprompter Manual, for Executives, Politicians, Broadcasters and Speakers. Laurie can be contacted through www.begreatoncamera.com, or 1-877.999.3433, or at email@example.com