I recently acquired one of these lenses for cheap, to serve as a fast aperture midrange zoom for a while. I used this extensively over a weekend-long retreat. I'd checked what few reviews I could find and knew it would not be as sharp as the Nikkor 24-70. While it is an AT-X Tokina and the build quality is great, I was not prepared for the issue I found with it. Below is an extreme example, shot at high sensitivity by firelight. It does however very well showcase what is happening when any light sources or other extreme contrast is present in the shot:
(Processed in Lightroom, with the luminosity turned all the way down in the blue and purple and green channels to darken some of... that)
For all but the lowest lighting (or need of shallower DOF) I think I am better off using the 18-105mm kit lens. I don't think I could sell images from this lens that include light sources or really heavy contrast. Landscapes or outdoor / ambient light stuff wouldn't be so bad, just make up for some of the sharpness by stopping down and/or increasing it in post, but I think a Nikkor 24-70 or 17-55 might be in order if I am going to take any paid work very soon.
