Why is there play on the knob of my FocusONE? Is something wrong? Ashley July 26, 2018 20:33 Follow The play on the knob is within the standards of the FocusONE! Please see the video below for further explanation: Related articles How do I align the FocusONE's control knob? How do I teach a new lens to the Motion Kit? FocusONE Comments 0 comments Please sign in to leave a comment.