This large aperture telephoto macro lens enables you to shoot up to 1:1 life size close-ups. Its large F2.8 aperture makes it an ideal lens for digital SLR as well as film SLR cameras.Two Special Low Dispersion (SLD) glass elements control various color aberrations and assure high image quality. Super Multi Coating gives superb color performance whilst cutting down flare and ghost. Its compact, yet advanced, construction has an overall length of Length 137mm (5.4in.), maximum diameter of 79.6mm (3.1in.), filter size of 72mm and weight of 895gr / 31.6 ounces. ?F2.8� large aperture tele-macro lens Tele macro lenses have a greater working distance. It is possible to enjoy Macro photography, even when you are far from subject. This enables you to capture the small animals and insects without disturbing them. Very narrow depth-of-field allows selective focusing and less distracting backgrounds. Large aperture of F2.8 is ideal for sports, action and indoor photography. It is equipped with two pieces of Special Low Dispersion (SLD) glass elements Two SLD glass elements control various color aberrations and assure high and sharp image quality. Hyper Sonic Motor (HSM) with full time manual focus override The HSM models provide ultra quiet high-speed autofocusing as well as full-time manual focus override. Floating Focusing System produces excellent optical performance A floating focusing system moves two different lens groups in the optical system to different positions. This system compensates for astigmatic aberration and spherical aberration. Since focusing does not change its overall length, this lens is easy to hold and use. Super Multi Layer Coating ?Super Multi Layer Coating� of this lens gives superb color performance whilst cutting down flare and ghost caused by reflections from the digital image sensor. APO Tele-Converter EX (optional) It is also possible to use this lens with Sigma 1.4x EX and 2x EX APO Tele-Converter. When this lens is used with the 1.4x EX or 2x EX Apo Tele Converters (optional), it becomes a 210mm F4 AF tele-macro lens or a 300mm F5.6 MF tele-macro lens respectively.