Review: Tamron AF 17-50mm f/2.8 SP XR Di II VC Zoom Lens for Nikon

I had five minutes to play with a sample of the new Tamron 17-50 lens at the camera store today. Here are my impressions based on test shots with my D90. The VC (vibration control) seems to work quite well, at least on par with Nikon's VR (vibration reduction). I was able to get sharp handheld shots down to 1/10th. I didn't try it at any slower shutter speeds but expect it would help out there as well. Autofocus is relatively quick, I can't say that it's as fast as my Nikon lenses but it certainly wasn't slow. The lighting in the store was ok, not great, but not extremely dark, so it's possible the lens would hunt more in adverse conditions. Build quality was decent, not on par with the Nikon 17-55 f/2.8 but certainly not flimsy. Lens felt well balanced on the camera smooth action in the zoom and focus rings. The big disappointment was image quality at f/2.8 - there was a lot of smearing of bright colors in high contrast areas. I've posted a couple of 100% crops below - check out the transitions between white and yellow to black to see the problem. These shots were taken at ISO 200, 50mm, 1/30th, VC on, RAW with no postprocessing, JPEGs exported from Capture NX 2 (full EXIF information is included). I didn't test anything other than f/2.8 because if you can't shoot wide open, why buy a fast lens in the first place? I expect that this problem diminishes as you stop down. Ultimately, I wouldn't recommend this lens based on image quality as observed below. At ~$650, it's less than half the price of the Nikon 17-55 but I still wouldn't call it cheap.