The Canon FDJ-P31 Focus Demand for DIGISUPER 27AF/86AF/100AF is a digital focus demand that controls the AF function of the DIGISUPER 27AF/86F/100AF studio box lens. Using the Digital Focus Demand with a compatible lens allows the operator to control the position and size of the AF target area, which is visible in the viewfinder. The focus demand clamps onto the pan handle of your tripod or pedestal providing you with control over the focus of your lens; it is designed for right hand operation.