I had actually prefer my Nikon-standard zoom AF-S DX exchange 18-70 f / 3.5-4.5 ED against something Brighter. An image stabilizer would be the movies of course very nice. My decision was ultimately on a Tamron 17-50 VC because Zoom / Focus at comparable Sigma turning in the wrong direction, which has totally annoyed me. After first tests, but showed that the sharpness decreases markedly in the left half in comparison with the right half. So I sent it with the camera to adjust to the Tamron Service. After two weeks I got back the stuff and tested again. It was a little better but still quite disappointing in direct comparison to the Nikon kit lens. Stopped down to the maximum aperture of the Nikkor was the Tamron at the edges still slightly weaker, but to pass for a adequate replacement, it should at least be as good. Haptic it is really great and also fully equipped with the image stabilization, but the performance offered was not good enough. Since there are many enthusiastic buyers, I think slowly, I had just caught only bad luck and not so good copy. That's really a shame, because features and feel are really great. If that topic definition is not so important, but so has an otherwise really great lens. To me it is very important especially in the wide-angle end, as I would have liked to use it for recording of starry skies. Who wants to see more comparison images, found in DSLR-Forum under the theme "Comparative AF-S DX Nikkor 18-70 f / 3.5-4.5 with Tamron 17-50 f / 2.8 (VC)" a link.
