Abstract: Methods and apparatus which are suitable for actuating a stage relative to a z-axis and supporting the weight of the stage against the force of gravity are disclosed. According to one aspect of the present invention, an actuator device includes a first arrangement, a magnetic system, a piston, and a guide bearing arrangement. The first arrangement includes a yoke and a center pole, and the magnetic system includes a magnet that is coupled to the yoke as well as a coil which cooperate to function as a voice coil motor. The piston supports at least a weight associated with the first arrangement, and the guide bearing arrangement includes a planar air bearing that enables the device to move over an external surface.