Canon EOS 5D Mark II EOS 5D Mark II Instruction Manual - Page 79

f: Selecting the AF ModeN One-Shot AF for Still Subjects Suited for still subjects. When you press the shutter button halfway, the camera will focus only once. When focus is achieved, the AF point which achieved focus will flash in red, and the focus confirmation light AF point Focus confirmation light in the viewfinder will also light. With evaluative metering, the exposure setting will be set at the same time focus is achieved. While you hold down the shutter button halfway, the focus will be locked. You can then recompose the shot if desired. In the d/s/f/a/F shooting modes, AF is also possible by pressing the button. If focus cannot be achieved, the focus confirmation light in the viewfinder will blink. If this occurs, a picture cannot be taken even if the shutter button is pressed completely. Recompose the picture and try to focus again. Or see "When Autofocus Fails" (p.84). If the [1 Beep] menu is set to [Off], the beeper will not sound when focus is achieved. AI Servo AF for Moving Subjects This AF mode is for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the subject will be focused continuously. The exposure is set at the moment the picture is taken. In the d/s/f/a/F shooting modes, AF is also possible by pressing the button. 79