The Sigma 30mm f/1.4 EX DC HSM is a large aperture lens that provides a standard angle most similar to the human eye. The 30mm focal length translates to approximately 50mm in 35mm format(*).  

A glass mold aspherical lens element at the rear group of the lens reduces color aberration and provides high-quality image results. From 15.7" (40 cm) minimum focusing distance to infinity, this lens creates very sharp images with high contrast, and can perform superbly in a great range of applications, including snapshots, portraiture, indoor shooting and landscape photography.

DC lenses are exclusively designed for digital SLR cameras. The image circle (rear of lens) is made to match the smaller dimensions used for the image sensor on digital cameras. As a result these lenses are also more compact and lightweight, and are better matched to digital SLR cameras.