The Izumar V-T is a large filter designed to… well, let me just quote the instructions: “The Izumar V-T Portrait Lens is designed to get the sharp image only in the center area and to reduce sharpness gradually at the outer parts on the 35mm film. The lens barrel can be moved, extended and retracted, so that you may have various vignetting effects depending on your subjects. […] We hope that you will take nice portrait pictures of your family, of your friend, or will take very attractive fashion pictures with this unique lens.” Fits lenses with 49mm filter threads.