There are four propellers on a quadcopter drone. They don't move (other than rotating the propeller) so to make the drone travel, the props in "front" reduce their speed causing the drone to tilt slightly and generate movement in that direction. The camera is on a device that moves in order to keep the camera view steady, so the front of the drone tipped down while the camera did not. That resulted in part of the drone getting into the shot.At about the 45 second point, the top half of the image goes dark. What caused that? (I don't fly a drone, so I am being curious, not critical.)