Abstract: A spotlight includes a housing with an illumination source moveably mounted therein and a lens assembly moveably mounted therein. One or more lenses are mounted in the lens assembly, each in one of a plurality of predetermined positions. Independent movement of the source and lenses conveniently provides a variety of field angles, light outputs, or other illumination characteristics. A reflector, framing shutters, iris, pattern grids, and color filter gels may also be used as desired.

Abstract: A lens casting or housing provides a series of grooves for selective mounting of various lenses to achieve various beam spreads. By spacing lenses in the housing, it is possible to reduce the diameter and thickness of the lens nearer the light source with consequent improvement in thermal characteristics as well as efficiency in light transmission.

Abstract: A spotlight housing has a rear section in which a lamp socket is accommodated. The lamp projects forwardly through the back of a reflector. The lamp socket is mounted on a heat sink. A coil spring is interposed between the heat sink and the rear section of the follow spot housing. A screw threaded rod projects from the back of the heat sink, through the spring and through a large clearance opening in the rear section of the housing where it connects with a positioning knob. The knob is urged against the outside surface of the housing, which is spherically formed with a geometric center located near the access opening to the reflector. By shifting the knob along the surface, the lamp filament can be moved laterally in any direction relative to the reflector axis or focus. By rotating the knob, the rod length changes as the spring compresses and expands, thus moving the filament more or less into the reflector housing as the heat sink limits rotation.

Abstract: A theatrical follow spot utilizes elliptic reflective optics to achieve compact size and non-astigmatic projection. A source lamp is situated in front of the mirror, sufficiently offset to one side thereof so as to be out of the path of reflected light. The mirror has the shape of an ellipsoid of revolution, the mirror section being entirely on one side of a meridian plane of the ellipsoid. The axis of light from the source lamp is coincident with a line through the near focus of the ellipsoid and the center of the mirror. This insures that an image in the near focal plane, such as the circular opening of an iris, will be projected at the distant focal plane of the ellipsoid, without distortion of shape.