Samyang 12mm T3.1 VDSLR ED AS NCS Fish-eye allows more delicate video work with T number marks. The focus gear ring is installed for follow focus system. You may change the aperture quietly and smoothly with the uncoupled aperture gear rings. Also, distance scale and T numbers are marked on both sides of the lens for convenience. Samyang 12mm T3.1 VDSLR ED AS NCS Fish-eye is a manual focus lens with a low T number. You may control the lens precisely when shooting under various exposure environment including relatively dark or too bright situations. This lens features 12 lenses in 8 groups including 2 glass aspherical lens (ASP), and 3 extra low dispersion lens (ED) to offer high resolution. Also Nano Coating System (NCS) of Samyang Optics is used to optimize the light penetration and minimizes flare and ghost. With such optical construction, it has 0.2m of minimum focal length to film subjects in near distance. Stereoscopic projection optical design delivers soft and stabilized fish-eye distortion effect.