(Other than don't do it). I tested it on a previous shoot inside the cab of a semi on an interstate, and the movement of oncoming cars passing by in the opposite lane out the driver's side window rendered the shot unusable because of the shutter angle on the x track. The cars had no motion blur it seemed. Is there some other technique for doing this kind of shot with HDRx? I had better luck on a different shot using HDRx where the angle of the lens to driver kept other cars out of the shot, but the angle was not something I liked very much. For some reason I once thought it possible to use a negative number for HDRx that would allow me to expose the the hot area of the shot properly while recording, and bringing the interior, unmoving dark foreground up in post. But maybe I imagined that ability.