In cinematography, the olly grip is the individual who operates the camera dolly. He or she places, levels, and moves the dolly track, then pushes and pulls the dolly and usually a camera operator and camera assistant as riders. If the dolly has a moveable vertical axis, such as a hydraulic arm, then the dolly grip also operates the "boom". If both axes are used simultaneously, this type of dolly shot is known as a compound move.