High performance, large aperture medium telephoto macro lens incorporating Sigma's Optical Stabiliser function.Sigma's medium telephoto macro lens incorporates Optical Stabilisation allowing the use of shutter speeds approximately 4 stops slower than would otherwise be possible. SLD glass provides good control of aberration and the floating inner focus system ensures high rendering throughout the focusing range. By using Sigma's APO Tele Converters, it is possible to take photos at greater than 1:1 magnification. HSM ensures a quiet and high speed AF as well as full-time manual focus override. This lens has a rounded 9 blades diaphragm which creates an attractive blur to the out of focus areas. Large aperture medium telephoto macro lens This medium telephoto macro lens allows you to maintain an appropriate distance from subjects while still getting close up photos. Since the working distance at its closest focusing position is 142mm, shadows of the lens and camera will not affect photography making it suitable for taking photos of subjects, such as flowers, under natural lighting conditions. In comparison to the Sigma 50mm and 70mm macro lenses, the main subjects can be defined with perfectly smooth and blurred backgrounds. High rendering performance The lens power layout produces excellent optical performance. High refractive index SLD (Special Low Dispersion) glass corrects chromatic aberration, spherical aberration and field curvature. It ensures high rendering performance at all shooting distances. The Super Multi-Layer Coating reduces flare and ghosting, maintaining quality images with high contrast. Handheld photography with ease Sigma's OS (Optical Stabiliser) system offers effective correction of approximately 4 stops. As the stabilisation effect is visible through the viewfinder, it aids composition and accurate focusing. * The OS effectiveness will gradually decrease as the shooting distance becomes shorter. Floating inner focusing This lens incorporates floating inner focusing which moves two lens groups separately. This minimises aberrations which occur as shooting distance changes and enables stable rendering of the image from infinity to 1:1 magnification. This also corrects image distortion, especially when taking close-up pictures. Since focusing does not change its overall length, this lens is easy to hold and use. Quiet and high-speed AF The HSM (Hyper Sonic Motor) provides quiet and high speed autofocus. It is also possible to use full-time manual focus, even if the lens is set to the AF position. Rounded 9 blades diaphragm This lens has a rounded 9 blade diaphragm which creates an attractive blur to the out of focus areas. This also creates smooth, rounded out of focus highlights when taking photos which have a strong light source in the background such as lights shining on the surface of water. APO Tele converters This lens is compatible with Sigma's APO Tele Converters. With APO Tele Converter 1.4x EX DG, it can be used as 147mm F4 AF* telephoto macro lens, and APO Tele Converter 2x EX DG as 210mm F5.6 MF telephoto macro lens. This allows a greater working distance while still achieving 1:1 macro magnification. *AF does not work from 0.45m close up photography. Dedicated hood adapter When taking photos with APS-C sized digital SLRs, the (supplied) dedicated hood adapter, which extends the length of the hood can be attached. This gives more protection from harmful light that could negatively affect image quality. *When taking photos with full-size digital SLR, please remove HA680-01 in order to avoid the edges of image being blocked.