The Sigma 24-70mm F2.8 DG HSM OS Art is a premium workhorse zoom lens designed for the latest high megapixel DSLRs. A constant aperture of 2.8 through the zoom range makes this a highly versatile tool and a brand new Optical Stabilization (OS) system helps compensate for camera shake. Brings a new level of usability and durability featuring a rugged metal barrel and an emphasis on image quality. | The aspherical elements used in the 24-70mm F2.8 OS Art undergo a highly precise level of polishing, producing elements thicker in the center than on the edges. This process creates stunning image quality and beautiful circular bokeh. | Handcrafted at Sigma's single factory in Aizu, Japan and undergoes individual evaluation before leaving Sigma's facility. Lens Construction: 19 elements in 14 groups | Full Frame Lens with APS-C compatibility | Angle of View (35mm): 84.1 deg - 34.3 deg | Number of Diaphragm Blades: 9 (Rounded diaphragm) | Minimum Aperture: F22 | Minimum Focusing Distance: 37cm / 15in. | Filter Size (mm): 82mm | Maximum Magnifications: 1:4.3 | Dimensions: (Diameter x Length): 88mm x 107.mm / 3.5in. x 4.2in. | Weight: 1,020g / 35.9oz.