How to Enable auto focus in video mode on the Canon 5D
Many people have complained about the lack of autofocus in video mode on the Canon 5D Mark II. Fortunately, this video demonstrates a solution by utilizing the live mode, thus enabling the still camera's autofocus features.
Some people are not aware that the "Live Mode" style of auto focus used in Live View can be used while shooting video on the 5D MK II. While this is less than ideal because of noise and change in the shot exposure, it is a way to have the camera verify that the shot is in focus.