The Rokinon 50mm T1.5 AS UMC Lens is a fast manual focus prime lens. It provides a very fast maximum aperture of T1.5 for effective low light capture and shallow depth of field control and an 8 blade iris for attractive bokeh. Optimized for cinema and video applications, the focus and aperture control rings are outfitted with industry standard gearing, which provides an interface for working with a traditional follow focus. The aperture control ring has also been de-clicked, which enables smooth iris pulls. In addition, bright aperture and distance markings are printed on the lens barrel facing laterally to facilitate easier control by a focus puller. The 50mm has a minimum focus distance of 1.5'. Internal focusing minimizes the effects of lens breathing, which insures a more consistent angle-of-view when adjusting focus. The lens is composed of 9 elements in 6 groups, including one aspherical element and one hybrid aspherical element to reduce aberrations. In addition, a lens multi-coating helps to improve light transmission reducing flare and ghosting. The filter thread diameter is 77mm. T1.5 F1.47ft