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 eyes field of vision. For use with smaller chip APS-c and 4/3 cameras only HSM (Hyper-Sonic Motor) ensures a quiet & high-speed auto focus Aspherical glass elements offer correction for distortion Special Low Dispersion (SLD) & ELD (Extraordinary Low Dispersion)glass provides optimum color correction & sharpness A lens hood, front/rear lens cap and carrying case are included with the lens. SpecificationsLens Construction 7 Elements in 7 GroupsAngle of View 45 (1)Number of Diaphragm Blades 8Mininum Aperture f16Minimum Focusing Distance 40 cm / 15.7 inFilter Size (mm) 62Maximum Magnifications 1:10.4Dimensions(Diameter x Length) 76.6 x 59 mm/3.0 x 2.3 inWeight 430g / 15.2oz.