Sigma 10-20mm f/4-5.6 EX DC HSM Lens Sony Alpha DSLR A700, A350, A300, A200, A100 SLR Digital Camera HSM (Hyper-Sonic Motor) allows for fast autofocus speeds & quiet shooting and is capable of full-time manual operation Three aspherical lens elements offer excellent correction for distortion Three SLD (Special Low Dispersion) glass elements employed for effective compensation of color aberration Internal Focusing System allows the convenient use of a polarizing filter for creative effects & improves the optical performance of the lens at various distances Awarded the TIPA award, best consumer lens in Europe '2006