<p>I have one of the early M4-2 motors #6597 which at the time had to be individuallly tweaked to a specific camera. It was very rough on the camera and ultimately destroyed the wind head, I'm quite convinced. at the time I enventually had 2 M4-2's and after the tweak, it would work on both cameras. wrecked the first one though. A turkey. bulky, heavy, and cumbersome. </p>