The lens features an internal focusing design, so the lens does not change its physical size when changing focus, which makes it compatible with rod-mounted accessories such as matte boxes. It incorporates standard 0.8 MOD focus and iris gears, allowing it to interface with standard lens accessories, and the bright yellow dual focus scales allows the lens to be easily read from either side of the lens. A 77mm filter thread allows you to attach an optional filter directly to the front of the lens.