The Sigma 17-50mm f2.8 EX DC OS HSM is a versatile wide-angle to telephoto zoom lens designed specifically for Nikon DX-format (APS-C) DSLR cameras. Featuring a constant f2.8 maximum aperture throughout the entire zoom range, this lens excels in available light and provides creative control for both landscapes and portraits. The optical design incorporates FLD (F Low Dispersion) glass elements with performance equal to fluorite, along with aspherical elements, delivering sharp, high-contrast images with excellent colour accuracy across the entire focal range. The Hyper-Sonic Motor (HSM) ensures fast and quiet autofocus performance, while the Optical Stabilisation system allows handheld shooting at shutter speeds approximately 4 stops slower than would otherwise be possible, making it ideal for low-light situations. An ideal companion for travel and everyday photography, this secondhand lens represents excellent value for photographers seeking a capable, bright zoom lens.