Canon EOS 5DS R Instruction Manual - Page 118

3 Customizing AF FunctionsN With the [22] to [25] menu tabs, you can set the AF functions to suit your shooting style or subject. 22: AI Servo AI Servo 1st image priority You can set the AF operation characteristics and shutter-release timing for the first shot with AI Servo AF. : Equal priority Equal priority is given to focusing and shutter release. : Release priority Pressing the shutter button takes the picture immediately even if focus has not been achieved. It is effective when you want to give priority to capturing the image rather than achieving focus. : Focus priority Pressing the shutter button does not take the picture until focus is achieved. Effective when you want to achieve focus before capturing the image. 118