Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 14-24mm F2.8 DG HSM is the longer of the two lenses at 135mm. The Tokina 16-28mm f2.8 Pro FX with a length of 133mm is 2mm shorter. Besides being longer, the Sigma 14-24mm F2.8 DG HSM also has a larger diameter of 96mm compared to Tokina 16-28mm f2.8 Pro FX's 90mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Tokina 16-28mm f2.8 Pro FX weighs 950g, 21% (200g) lighter than the Sigma 14-24mm F2.8 DG HSM's weight of 1150g.
Below you can find the dimension and weight table of the 'Wideangle Zoom Lenses in Nikon F (FX) Mount for size comparison purposes.
Wideangle Zoom Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both Sigma 14-24mm F2.8 DG HSM and Tokina 16-28mm f2.8 Pro FX has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 14-24mm F2.8 DG HSM is also available in Canon EF and Sigma SA mounts.
Tokina 16-28mm f2.8 Pro FX is also available in Canon EF mount.
Focal Range
Sigma 14-24mm F2.8 DG HSM has a focal range of 14-24mm and 1.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 21 - 36mm.
Tokina 16-28mm f2.8 Pro FX has a focal range of 16-28mm and 1.8X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 24 - 42mm.