Sigma 28-300mm f/3.5-6.3 DG IF Macro Aspherical Lens for Pentax and Samsung SLR Cameras Compact high performance zoom lens with a 10.7x high zoom ratio, 28 to 300-millimeter focal length Special low dispersion glass and aspherical lenses produce high level of optical performance 19.7-inch minimum focusing distance with macro mechanism for close-up photography at full zoom Zoom lock device prevents zoom setting from being changed inadvertently Designed for Pentax digital SLR cameras