"Our visual system picks up edges and other areas of high contrast to detect motion, so in areas of high contrast any non-smoothness of the images motion will be more noticeable."
http://www.xdcam-user.com/2011/07/m...0-and-other-video-cameras-at-low-frame-rates/
http://www.xdcam-user.com/2011/07/m...0-and-other-video-cameras-at-low-frame-rates/