The lens moving mechanism may be a cam structure. The cam structure is set
so that the rotation axis of the lens is held at the center of the dome
in a predetermined center hold angle range corresponding to the direction
of an elevation angle, and that the rotation axis of the lens is moved
from the center of the dome in the zenith direction at angles lower than
the center hold angle range. Good images can be obtained even when
shooting in the direction of a depression angle.