Samyang 500mm f/8.0 Mirror Lens is a welcomed addition to any sports or wildlife photographer's kit bag. It's lightweight and compact and it focuses as close as 5.6' (1.7m). The aperture is fixed at f/8.0. This manual focus lens is constructed from fully multi-coated low-dispersion optical glass with a 72mm front filter thread and a 30.5mm rear filter thread. A 2x neutral density filter, 4x neutral density filter and a skylight filter (all 30.5mm) are included. A T-ring adapter (available separately) is required to mount this lens to a camera body.