I saw a video recently where they studied this very thing with video.They found that most does got nervous when they saw the camera and most bucks,from yearling on up,actually spooked.They determined it was the sight and later smell of the camera that the deer reacted to.
They experimented with moving the camera to about 6' high and that just about eliminated the problem.
They had less spooking around food plots,possibly because the deer were there frequently and may have gotten used to the cameras.
It was a well done and interesting piece.Called "Trail Cameras:What You've Been Missing".