Focus tracking calculations for cinecamera lose precision when panning camera (moving tracking subject to edges of frame)

Focus tracking calculation is off for keeping focus sharp on tracked object when object moves away from center of camera lens

1. Add cinecamera actor to scene
2. Increase sensor size to iMax preset (to accentuate issue)
3. Set Focus mode to Tracking and select object close to camera
4. Turn on Draw Debug Focus plane
5. Pan cinecamera back and forth so object moves from left to right sides of frame and observe focus plane movement in top down view (does not stay locked on subject)