The canon fit sigma 10 20mm f35 ex dc hsm is a super wide angle lens with maximum aperture of f35 throughout the entire zoom range it has 2 eld glass elements and 1 sld glass element which provide excellent correction of colour aberrations 4 aspherical lenses provide correction for distortion and allow its compact and lightweight construction it also features a hyper sonic motor which enables quiet and high speed auto focus the sigma 10 20mm f35 ex dc hsm lens is designed for digital c