Sigma 35mm F1.4 DG HSM is an Auto Focus (AF) Wideangle Prime lens with 35mm FF max sensor coverage. When mounted on a 35mm FF sensor camera, it will give you an FF equivalent focal range of 35mm. Providing a max aperture of f1.4 at 35mm, this lens is very fast.
Sigma 35mm F1.4 DG HSM is not a weather sealed lens, so you have to be extra careful against rain and dust.