Produces a broad wash of light, with little control over the beam shape. Used for lighting large areas at short throws, or illuminating the cyclorama . The reflector may be either asymmetric or symmetric . An operator moves the whole body of the lantern to direct the beam and follow performers as required. Some low-end followspots are directly derived from profile spots, whilst professional units are ofte n designed from scratch.
Larger units use discharge lamp s for a brighter beam.
Due to the long throw distances over which the larger units are used, their beam angle s are often very small. Perhaps the most famous followspot is the Strong International Super Trouper . The diameter of the beam can be varied by varying the distance between the lamp and the lens . The name comes from the French physicist who invented the lens shape used. The lens is a series of stepped rings, each with the curvature that a plano-convex lens of the same diameter would have at that radius.