Rokinon 500M 500mm F/8.0 Mirror Lens (Black) Aperture: Fixed F/8 7 Elements in 6 Groups Filter Size: 72mm Minimum Focusing Distance: 5.6 ft Includes ND-2X, ND-4X and Skylight rear-mount filters, lens caps, lens pouch, instruction manual, and 1 year Rokinon warranty