|The zero position of the rear swing is established when the camera is in its closed position. To maintain this square position, tighten the swing lock and leave it tightened when the camera is opened. To establish a squared up position when the camera is open, loosen the swing lock and the center lock so that both the left and right slides are free to slide, then pull them back so that they protrude slightly beyond the back of the camera frame. With a thumbnail on the back of each slide, push the slides forward so that they are even with the back of the camera frame. First tighten the center lock knob then the swing release knob. The back is now square.