The 50mm T1.5 AS UMC Cine DS Lens for Canon EF Mount from Rokinon 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.