The legendary Tokina
Tokina AT-X history
Angenieux 28-70mm f:2.6 AF
1) AT-X Tokina AF 28-70mm 1:2.8 Ø 72 JAPAN
2) Tokina AT-X PRO AF 28-70mm 1:2.6-2.8 Ø 77 JAPAN (Pro I with screw on hood)
3) AT-X PRO 28-70mm 1:2.6-2.8 Ø 77 JAPAN (Pro II with Bayonet hood)
4) Tokina AT-X Pro 28-80mm 1:2.8 (gold badge on focusing ring)
5) Tokina AT-X PRO SV 28-70mm 1:2.8 Ø 77 JAPAN
NOTE1: The best performing of all these is the original Pro version which this article is about. Second place goes to the Pro II version though some may argue that the Pro II version should grab the title of best performer in this group. If i was forced to give a numerical value from 1 to 10 on these lenses, then i would probably give both of these a 8,5 so the best buys are the Pro I and Pro II versions. The 28-80 would take 3rd place with a solid 8 and the SV version would take last position with a 6.
NOTE2: All of the aforementioned lenses share similar naming conventions which confuses a lot of people and reviewers alike. So be sure to identify the right lens when involved in a forum discussion. They may seem similar but they are each unique and different. Some may wonder why did Tokina ever stray from the original design and I think it had to do with cost cutting.
Focusing and handling
Focus Clutch Mechanism
Optical performance in detail
The original Pro version also has a different rendering of the OOF areas and seems to have better bokeh. Like the rest of its family relations it's a bit lacking in the coating department so care must be taken when shooting with a bright light source within the taking frame. Allow me to be more specific here in saying that performance can be maximized by protecting the front element from both dirt and stray light. So keep that front and rear element as clean as possible and try to find a good hood to use. You should also know that the use of a protector filter such as a cheap UV is prohibited since this will only multiply the problem of this lens to flare or ghost (you've been warned). The lens offers a non-rotating 77mm filter mount and should only be used when a polarizer is needed.
Closing down to f/3.5 improves sharpness and contrast a lot and this is important to know. By f/4 the images produced on a FX sensor are non distinguishable from any Nikkor and by f/5.6 it performs just as well as any Nikkor even on a DX sensor. What this means is that since this is not a high resolving lens like the Nikkor, it performs better on the 12MP FX sensor than it does on the demanding 12MP DX sensor.