First impressions of the Tokina 28-70 2.6-2.8: Build quality is great however the zoom ring is slightly harder to turn on the wide end. The images are really nice, its not as sharp as the Sigma 18-35 wide open but it not far off. The Tokina renders slightly warmer and appears to have more distortion however I think that the Tokina's images look more pleasing than the Sigma's