Tokina's constant f/4 APS-C ultra-wide — wider than the 11-16mm with more versatile range.
The Tokina AT-X 12-28mm f/4 Pro DX was released in 2012 as a constant f/4 ultra-wide zoom for Nikon F-mount APS-C (DX), covering 18-42mm full-frame equivalent. Fourteen elements in 12 groups including aspherical and SLD elements. Nine rounded aperture blades. 77mm filter thread. At 540g. 0.25m MFD constant across the full zoom range.
Fourteen elements in 12 groups (2 aspherical + 2 SLD elements). Nine rounded aperture blades. The 77mm filter thread. At 540g the lens is moderate. Minimum focus distance of 0.25m (constant throughout zoom range). Motorised AF. f/4 constant aperture. DX APS-C image circle (18-42mm equivalent). Nikon F DX mount.
The constant f/4 aperture across 12-28mm is the practical advantage: unlike variable-aperture ultra-wides, f/4 provides consistent exposure and depth of field across the full range. The constant 0.25m MFD throughout the zoom means close focus distance does not change when zooming. The SLD (Super-Low Dispersion) elements reduce lateral chromatic aberration across the ultra-wide range.
On the used market the Tokina AT-X 12-28mm f/4 Pro DX is affordable as a DX ultra-wide zoom for Nikon. Condition checks: AF response, 77mm front element for marks, zoom ring smoothness. DX only — vignettes on FX. Compatible with Nikon F-mount DX APS-C bodies.