I bought this lens for my Nikon D5000. Unfortunately, it turned out rather quickly that it's not really sharp. Until Aperture f = 5.6, I had to get a little direction 'infinite' readjust to sharp images in most focal lengths the sharpness. So I have the lens and my camera wrapped and both brought to Sigma to Rödermark. As usual the reception was very friendly and professional; you said that he would look into the matter promptly ... Four days later, I got the camera and lens well packaged via DHL back home. Since then, 'sits' focus and I am with the performance of the zoom very satisfied - if each closes the aperture at least one value. - At maximum aperture I feel the images as something to 'soft' but are not blurred.
The second thing that bothers me somewhat, is the here already often mentioned backlight sensitivity. - Still, I'm with the 'Contemporary lens' overall quite happy and forgiving 4 stars!
