High ratio zoom lens housed in a compact construction and incorporating Sigmas original OS (Optical Stabilizer) function. This telephoto zoom lens incorporates Sigmas original OS (Optical Stabilizer) function and is housed in a compact construction. The OS function offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible. The SLD (Special Low Dispersion) glass element provides excellent correction for all types of aberrations. High image quality is assured throughout the entire zoom range. The Super Multi-Layer Coating reduces flare and ghosting and provides high contrast images throughout the focal range. This lens has a minimum focusing distance of 150cm (59.1) throughout the entire zoom range and a maximum magnification ratio of 1:3.9, making it ideal for close-up photography.This lens is equipped with Sigmas own unique OS (Optical Stabilizer) function. This system offers the use of shutter speeds approximately 4 stops slower than would otherwise be possible. It makes telephoto shooting easy for many types of photography such as sport and nature. For Sony and Pentax mount, the built-in OS function of this lens can be used even if the camera body is equipped with an anti-shake function. As compensation for camera shake is visible in the view finder, the photographer can easily check for accurate focus and ensure there is no subject movement. * For Pentax and Sony mount, it is not possible to use AF and stabilizer function (OS) when attaching to film SLR, Pentax ist* series and K100D DSLR cameras.