Technical cameras are characterized by the possibility of "movement," i.e., the lens's shifting in relation to the image recording part, be it an analog or digital back. These movements (rise, fall, shift left/right) are used either a) for perspective correction to precisely control converging lines or b) to use the image circle of large format optics for planar stitching. Both types of movement place high demands on the precision and durability of the cameras. ALPA cameras are equipped with multiple high-precision (and therefore not cheap) roller bearings for this purpose and do not merely let greased metal friction on each other.