This Sigma 30mm F1.4 EX DC HSM lens, built for professional use, is a high quality prime lens suitable for professional use delivering outstanding optical performance for the discerning photographer. As a large aperture standard lens for digital cameras with a fast 1.4 aperture makes handheld shooting in dim light possible. 30mm corresponds to the diagonal of the imaging sensor found on most small chip cameras and as such, functions as a "normal" lens closely replicating the human eye's field of vision.