The samyang 135mm t22 vdslr is a manual focus lens with canon ef mount that allows for delicate artistic video work the focus gear ring is installed for follow focus system you may change the aperture quietly and smoothly with the uncoupled aperture gear rings also distance scale and t numbers are marked on both sides of the lens for convenience this telephoto lens expresses vibrant colour and soft out focusing area which makes it the best lens to shoot portrait night scenery wild life