Have the glass bought almost a year ago and now made thousands of images with it! For me it's the perfect telephoto zoom! The Sigma 50-150 is very compact and light for such a fast aperture telephoto lens. It is extremely sharp at every aperture and focal length, it has a faster unerring AF on my Nikon D80 and a universal focal length range for everything from portrait to Zoo. Five star, but would also be given six ..., -)