The sigma 24 35mm f2 dg hsm art lens is the worlds first large aperture full frame wide angle lens offering a bright f20 aperture throughout the zoom range it allows photographers to carry one lens to do the work of three fixed focal length lenses a 24mm 28mm and 35mm with f2 brightness and top optical performance premium fld glass with performance equal to flourite and seven sld glass elements allow for outstanding image quality an updated af algorithm makes for smooth accurate and