The samyang 85mm t15 as if umc ii lens is a fast medium telephoto prime designed for shooting high quality video on sonys full frame compact system cameras such as the a7 models the gearing on the focus and aperture rings allow you to follow focus and provide you with aperture control from a professional camera rig the aperture ring has also been de clicked which enables smooth iris pulls the focal distance and aperture settings are clearly marked on the side of the lens barrel for conv