I’ve recently gave to a friend my two Nikon lenses, the 50mm f1.8 AF-D and the 18-70 3.5-4.5 AF-S, in exchange for his Sigma 28-105 AF-D for a couple of weeks (he had to go to Sweden).
I had the chance to try the Sigma for an afternoon, I had to take some shots of stuff to sell and..well, it is simply awful compared to the Nikon. Not only the autofocus is much slower, but also the zoom ring is much harder to turn. And I’ve done no sharpness or the like comparison, I think I already know the winners. As Ken Rockwell says, if you need to buy a lens, don’t buy Sigma or Tamron. If you really are adventurous, go for Tokina, but otherwise stick with the camera producer. I’ll pay some more, but you get much more!
