Samyang's 24mm T1.5 ED AS IF UMC II Video is a wide-angle, manual focus cine lens designed for full frame & smaller sensor sizes & is known for its beautiful bokeh. It has been carefully engineered for professional film & video work, with the focus gear ring allowing the use of follow focus systems. The decoupled (de-clicked) aperture ring works quietly & smoothly during shooting. The stated T number of 1.5 refers to the actual light transmission of the lens & is particularly important in the film industry where light readings are normally made manually. A detachable petal-shaped lens hood is supplied.