This 10-20 mm f/3. 5 EX DC HSM wide-angle zoom lens from Sigma will bring a 102. 4° angle of view to your digital SLR. This means that although the sensor in your DSLR may be smaller than 35mm film you'll still be able to achieve sweeping perspectives & capture tight spaces with ease. Sigma's ELD & SLD lenses effectively correct chromatic aberration to ensure the 10-20 mm f/3. 5 EX DC HSM captures high-quality shots. Four aspherical lenses correct distortion while also making for a compact design. Plus, the hypersonic motor (HSM) ensures quiet, near-instant focusing of up to 24 cm.