sentences:  This "dolly-out/zoom-in" method involves the camera physically moving away from a subject whilst simultaneously zooming in (a similar effect can be achieved in reverse), so that the subject retains its size in the frame, but the background's perspective changes.Hitchcock used the effect to look down the tower shaft to emphasise its height and Scottie's disorientation.Following difficulties filming the shot on a full-sized set, a model of the tower shaft was constructed, and the dolly zoom was filmed horizontally.