Could the Tokina 12/24 be used as a close-up portrait lens. To my opinion, yes. This picture shows a close range view of items and one can see that the field deepth is very narrow, allways as much as a normal 100 mm 2.8 lens. The Dof in the foreground and background of the glas of red cabbage is excellent and just what one looks for on close range portrait or close range sports shots as well as interviews.
Also, in opposite to all other lenses I use, there is no under-exposure noticed with the Nikon D70.
The Tokina is very generous in light and exposes straight on all values. Other lenses push the D70 to underexpose and measured values give the D70 to expose at 160 ISO when set to 200 ISO. So, if underexposure is wanted, the Tokina 12-24 need a manual correction to reach that goal.