The Focus Mode
This setting is used to determine how the camera focuses using a selector switch on the front of the camera. The switch will either leave you to manually focus using the lens rings, or engage the auto focus. Within the camera menus you can select a specific auto focus method, here are a couple choices you’ll find:
S (Single): Camera focuses automatically and focus is locked when shutter release button is pushed down half-way. If the shutter button is relaxed, focus will be relax also. Use when your subject is relatively stationary such as landscapes. Useful to use when you want to the focus on an area different than the center of the view then recompose the image then release the shutter.
C (Continuous Autofocus): Camera continuously focuses automatically when shutter release button is pushed down half-way. Use whenever your subject might move.
M (Manual): The camera will not focus automatically. You must adjust focus manually by rotating the focus ring on the lens. When focus is achieved, the focus indicator in the viewfinder display (lower left corner) will light up. Use for macro photos or if the camera isn’t able to automatically focus.