Large Aperture: Bright f/1.4 maximum aperture suits working in low-light conditions and also affords greater control over the depth of field. Integrated manual aperture ring for tactile exposure control; this ring also features an 'A' position for automated, camera-based aperture selection
STM stepping motor: The SMT stepping motor enables quick, quiet, and precise autofocus performance along with a full-time manual focus override. Additionally, an internal focusing design maintains the overall lens length during use for improved handling and quicker response
Auto & Manual Adjustment: To adjust the aperture automatically, turn the aperture knob at the bottom of the lens to A, which means the camera controls the aperture; To adjust manually, turn the aperture ring at the bottom of the lens directly by hand
HD Nano: The lens adopts HD Nano Multilayer Coating & STM Step Motor, 11 elements in 10 groups, 9 aperture blades, including 2 ED lenses and 2 high refraction index lenses
Build in USB port for the firmware to reach compatibility for the newest cameras model and supports EXIF information transmission