Tamron 17-50 2.8 (non-VC) ou Sigma 17-50 2.8 VC.
Mmmh, voici un test entre les deux et justement sur un D7000 (ici, le Tamron est VC) :
http://francoismalan.com/2012/04/fast-s ... sed-17-50/Ce qui m'inquiète : " At the wide end (17mm) the Sigma’s focussing was intermittently unreliable (more about this later), and even when AF worked correctly the result it was softer than the Tamron. At 50mm f/2.8 the Sigma came into its own and delivered better sharpness and contrast...
However I was disappointed to see that at wide angle and especially longer distances (> 10m) the AF was intermittently unreliable, randomly alternating between hit and miss. Furthermore this lens, unlike the Tamron, often missed focus using my Nikon D7000′s live view! This is very strange and unexpected since “live view” focussing usually succeeds regardless of a lens’ focus calibration. It seems as if the AF crosses the in-focus point too quickly for the camera to realise it, and then incorrectly settles on the wrong focus. Even worse than refusing to focus, the camera reported a focus lock but this was at the wrong focus distance. It could be that my copy was a dud – I am currently considering returning it to the dealer."
J'ai trouvé une annonce pour un Sigma à 325 € (pas cher) mais je suis définitivement maudit avec ces histoires de focus