The Sigma 50-100mm F1.8 DC HSM Art series lens replaces their old 50-150mm F2.8 DC HSM lens. This lens while not reaching as far, provides one added stop of low-light performance over the 50-150mm, giving you cleaner images in low light, with more detail. The lens is sharp throughout the range and makes a good multi-purpose lens for all kinds of photography on DX cameras from portraiture to sports and lowlight.