Samyang Optics 8mm T3.8 VDSLR UMC Fish-eye CS II is a manual fish-eye lens designed for APS-C sensor size. Samyang 8mm T3.8 VDSLR UMC Fish-eye CS II is specially designed for professional film and video work, so the focus ring is installed for the follow focus system. With the detached aperture ring gear, you can change the aperture quietly and smoothly. The T-number, which determines the actual amount of light transmission, and the distance scales are marked on both sides of the lens for very precise filming. The lens operates in the manual low T-number aperture system, which allows you to shoot naturally under different lighting conditions.