Sigma 30mm F1.4 EX DC HSM is an Auto Focus (AF) Standard 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 45mm. Providing a max aperture of f1.4 at 30mm, this lens is very fast.
Sigma 30mm F1.4 EX DC HSM is not a weather sealed lens, so you have to be extra careful against rain and dust.