Abstract: An illumination lamp including a frame formed of plastics material support boards (10-12) mounted in parallel relation perpendicular to the main axis of the lamp and spacers (14, 16) spacing said support boards from one another. Mounted on the frame is an illumination source (24), projecting a beam of light therefrom along the main axis of the lamp. A gobo disk (44) rotatable about an axis parallel to the main axis and includes a plurality of shaped apertures (52-57) distributed circumferentially of the gobo disk and selectively positionable in the beam; an iris (40) is mounted forwardly of gobo disk and a lens assembly (36) is mounted forwardly of the iris. The lens assembly (36) is moved so that its focal point is either accurately in the plane of gobo disk (44) or in the plane of the iris (40).