Dynamic relocation of virtual machines among hypervisors in a domain is provided. During focusing from the farthest object to the nearest object, the first lens group is fixed, and the second lens group and the third lens group are moved along the optical axis. A structure for raising and lowering the cradle is provided and a cable connects the cradle to the structure for raising and lowering the cradle. A transistor is positioned in each of the plurality of semiconductor regions. The constant-voltage path includes a Zener diode and a resistor.