This video focuses on the inertial stabilization module (ISM), but the imagery is from a D48E in motion. In the stabilized images, the pan tilt unit (PTU) is moving.www.youtube.com/watch?v=cP8jYKoN5Nw
The smoothness of the pan is a function of the step rate. The higher the speed in steps/sec, the smoother the movement. A smaller step size allows a higher steps/sec rate for the same rotational (degrees/sec) speed. Therefore, a smaller step size results in smoother motion.