The Sigma EX DG APO HSM lens has a focal range of 70 mm to 200 mm and a constant maximum aperture of f/2.8 for use in taking long distance photos. The motor is almost completely silent, and the Sigma lens has internal focusing and rotating so that the lens does not change the length and the front element doesn�t rotate. The autofocus lens has a minimum focusing distance of 5 feet, 9 inches, which makes it work better for mid-range and distance shots rather than close-ups. The Sigma EX DG APO HSM has a weight of 43 ounces and is 7.2 inches long with a width of 3.39 inches. The Sigma lens also has a tripod ring to make it easier to affix the camera and lens onto a tripod for maximum stability. The ring is also removable to make shooting easier. This autofocus lens has a hood that prevents extraneous light from distorting the image. The filter diameter of the Sigma EX DG APO HSM is 77 mm.