Sigma DG 150-500mm f5-6.3 APO HSM OS for Nikon FThe Sigma DG 150 500mm f5 6. 3 APO HSM OS is a long lens with a long name. This is a long range supertelephoto zoom lens with pretty solid optical performance. The optical image stabilizer helps keep things steady, and a large grip tripod foot makes for easy handling. Cosmetic condition is decent, with some finish wear; the worst of it is on the (otherwise fine and functional) tripod foot, where the "non slip" coating is peeling and lifting in parts.