This 50-500mm f/4.5-6.3 APO DG OS HSM Lens for Sony/Minolta from Sigma is a zoom lens for digital SLR cameras with a Sony/Minolta lens mount. The lens has a standard to ultra telephoto zoom range that is ideal for nature, wildlife, or sports photography. The range translates into an equivalent 75-750mm when used with digital SLR cameras with an APS size chip. The lens is also compatible with full frame cameras. You can even increase your telephoto range by using the Sigma APO teleconverters.The OS (Optical Stabilizer) system minimizes image blur caused by camera shake, and offers the equivalent of shooting at a shutter speed 3-4 stops faster. This allows handheld telephoto zoom shooting even in poorly lit conditions.The use of the OS (Optical Stabilizer) system, HSM (Hyper Sonic Motor), APO (Apochromatic) design, four elements of SLD (Special Low Dispersion) glass, and multicoated optics all enable this lens to provide a high level of performance throughout its entire zoom range. A rear focus system insures quick, convenient manual focus and a non-rotating front barrel.The improved DG lens design corrects for various aberrations. This lens is specially coated to get the best color balance, while cutting down on ghosting caused by reflections from the digital image sensor. The lens provides the utmost correction against lateral chromatic aberration, which is a serious problem for digital SLR cameras.Note: The filter size of this lens is 95mm and the lens is supplied with a step down ring enabling digital cameras with an APS-C size image sensor to use an 86mm filter.Note: It is not possible to use a polarizing filter with the step down ring. If you attach a polarizing filter, you may not be able to remove it from the lens again.Note: It is not possible to use the AF and the built-in OS function of this lens when attaching it to film SLR camerasNote: If the camera body does not support the HSM motor, autofocus will not workDesigned 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 75 to 750mm with most cameras.The standard to ultra telephoto zoom range makes this perfect to carry when you only have room for one lens.The OS system uses two sensors inside the lens to detect vertical and horizontal movement of the camera. It works by moving an optical image stabilizing lens group, to effectively compensate for camera shake. It automatically detects movement of the camera and compensates for camera shake when shooting a moving subject such as motor sports.The HSM (Hyper Sonic Motor) system ensures quiet and high-speed autofocusing with full time manual focus override.Four Special Low Dispersion (SLD) elements provide excellent correction for chromatic aberration.The improved DG lens design corrects for various aberrations.Super Multi Layer (SML) coating reduces ghost and flare.