The 16-50mm f/2.8 DT Standard Zoom Lens from Sony is a bright zoom lens, specifically designed for Sony Alpha-series of DSLR cameras. When used with cropped APS-C sized DSLR cameras, the 35 equivalent focal length for this lens becomes that of a 24-75mm zoom. It is constructed of 16 elements in 13 groups, as well as Aspheric and Extra-low Dispersion (ED) glass elements, which all help to deliver sharp, clear photos throughout the zoom range. It has a minimum focusing distance of 1.0' and a front-end filter diameter of 72mm. Its aperture is constant throughout the zoom range, and will remain f/2.8 as your chosen focal length increases. It also has 7x circular aperture blades that work to produce smooth, out of focus background effects.