The samyang 35mm t15 as umc ii vdslr is a fast manual focus cine dslr lens suitable for full frame and cropped sensors aps cdx the lens has been developed primarily for professional video making purposes and features follow focus gearing and a de clicked aperture ring to allow smooth precise control over the focus and aperture whilst filming the t number of 15 refers to the actual light transmission which is more accurate and is particularly important in the film industry where light