This range of lenses is of the plano-concave variety. These lenses consist of one inward curved face and one flat face. The main attribute of a plano-concave lens is to bend the parallel input rays so that they diverge away from one another on the output side. This type of lens is widely used within image reduction or to spread light. Plano-concave lenses are typically used for beam expanders. Plano-concave lenses are also known as a tube-length correction lens in microscopy and as a barlow lens in astronomy. The Plano-concave lenses stocked here are our high quality grade BK7/SF11 type or equivalent. Knight Optical stock a range of high quality plano-concave lenses which are uncoated or AR coated. Antireflective coated versions have a multilayer AR coating for 450-900nm.