The latest L-Series hybrid lens featuring an iris ring for manual iris control during video capture.. A Nano USM is used for floating focus and a Voice Coil Motor (VCM) for rear focus which allows for quiet independant or synchronized actuation at high speed, great for video.. Improved durability and weather-resistant construction for use in harsh environments helps ensure reliability and dependability.. Incredibly minimal focus breathing.. Air Sphere Coating (ASC) helps significantly reduce lens ghosting and flare.