The Samyang 500mm f8 is a manual focus telephoto lens using the universal T-Mount system. The preset aperture control uses two rings: the first sets the desired aperture, and the second closes or opens the iris. The simple but effective 4 element multicoated optical design gives excellent results for the modest price. The T2 mount is extra and simply screws in place; the advantage of this being that if you change your camera it's inexpensive to convert the lens to fit it. The lens has a built-in tripod mount collar and comes with a protective case.