Rokinon 8mm f3.5 Fisheye is a Manual Focus (MF) Wideangle Fisheye Prime lens with APS-C / DX max sensor coverage. When mounted on a APS-C / DX sensor camera, it will give you an FF equivalent focal range of 12mm. With a max aperture of f3.5 at 8mm, this is a moderately fast lens.
Rokinon 8mm f3.5 Fisheye is not a weather sealed lens, so you have to be extra careful against rain and dust.