Canon EOS 6D Mark II Basic Instruction Manual - Page 110

f: Selecting the AF OperationN AI Servo AF for Moving Subjects This AF operation is suited for moving subjects when the focusing distance keeps changing. While you hold down the shutter button halfway, the camera will keep focusing on the subject continuously. The exposure is set at the moment the picture is taken. When the AF area selection mode (p.113) is set to Automatic selection AF, focus tracking will continue as long as the Area AF frame covers the subject. AI Focus AF for Switching the AF Operation Automatically AI Focus AF switches the AF operation from One-Shot AF to AI Servo AF automatically if a still subject starts moving. After the subject is focused in One-Shot AF, if the subject starts moving, the camera will detect the movement, change the AF operation automatically to AI Servo AF, and start tracking the moving subject. 108