Sigma 70-300mm f/4-5.6 DG Macro Telephoto Zoom Lens with Opteka 58mm UV Filter for Canon EOS SLR Cameras Including the 10D, 20D, 30D, 40D, 50D, Digital Rebel XT, XTi, XS, XSi, & T1i

Designed for use with full frame digital SLR cameras. May also be used with smaller APS-c size sensors with a corresponding effective increase in focal length to about 100 to 450mm with most camerasMinimum focusing distance of 59 inches throughout the entire zoom range & a maximum magnification ratio of 1:2. Equipped with a switch that reduces the minimum focusing distance at 150mm to 95cmSLD (Special Low Dispersion) glass elements provide optimum color correction & sharpness throughout the

Source: Digital Camera and Video Store...