The Zeiss 21mm f/2.8 lens with T* coating for Canon EF mount cameras is a high quality wide angle lens that works perfectly on either full frame or crop sensor cameras. Superior image quality in terms of sharpness, color accuracy and contrast. Completely manual focus however your camera will tell you when it's in focus! An all metal construction feels great in your hand and handles well when you're shooting. The lens has an 82mm filter thread.