The movements DECREASE depth of field. They change the location of the plane, but a tilted plane winds up with less depth front to back than the plane parallel to the film.
Originally Posted by gongman5000
In general, a constant linear aperture across film formats (when enlarged to the same viewing size print) leads to similar DOF. HOWEVER, the 'world' becomes more like a close up object the larger the film format, so that will decrease DOF more for the large format camera at closer distances. This really will come into play starting around 12 feet or so for an 8x10 camera.