Metabones Canon EF Lens to Sony E Mount T Smart Adapter (Mark IV) True electronic integration of aperture diaphragm - let camera automatically choose aperture in P or S exposure modes, or dial in yourself on the camera body in A or M modes. Flocking material coating inside the inner hole to reduce the internal reflection. High performance 32-bit processor and efficient switched-mode power supply. Wide open button (opposite of depth-of-field preview function) makes manual focusing easy. The inner hole is painted with flocking material coating. This can further reduce the internal reflection.