The Sigma 50-150mm f/2.8 II EX DC HSM is a compact, lightweight telephoto zoom lens specifically designed for Nikon F-mount digital SLR cameras with APS-C sensors. This constant f/2.8 aperture lens delivers sharp performance across its entire 50-150mm range, offering an equivalent focal length of 75-225mm on APS-C bodies. The HSM (Hyper Sonic Motor) autofocus system provides fast, silent focusing with full-time manual focus override capability. With its robust optical design featuring SLD glass elements for superior chromatic aberration correction, this secondhand lens is an excellent choice for telephoto work, portrait photography, and professional-grade zoom versatility at a fraction of new pricing.