The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tokina 16-50mm f2.8 DX and the Sigma 15mm F2.8 EX DG Fisheye for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is a crucial factor to consider when comparing two lenses. Tokina 16-50mm f2.8 DX is the longer of the two lenses at 97mm. The Sigma 15mm F2.8 EX DG Fisheye with a length of 65mm, is 32mm shorter. Besides being longer, the Tokina 16-50mm f2.8 DX also has a larger diameter of 84mm compared to the Sigma 15mm F2.8 EX DG Fisheye's 74mm diameter.
The weight of a lens is equally significant as its external dimensions, particularly if you intend to handhold your camera and lens combination for extended periods. Sigma 15mm F2.8 EX DG Fisheye weighs 370g, 39% (240g) lighter than the Tokina 16-50mm f2.8 DX's weight of 610g.
Lens Mounts
The Tokina 16-50mm f2.8 DX has the Canon EF lens mount whereas the Sigma 15mm F2.8 EX DG Fisheye has the Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and Nikon D6, Nikon D780 and Nikon D3500 for the Nikon F (FX) Mount.
Tokina 16-50mm f2.8 DX is also available in the Nikon F (DX) mount.
Sigma 15mm F2.8 EX DG Fisheye is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Tokina 16-50mm f2.8 DX has a focal range of 16-50mm and
3.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
25.6-80mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 15mm F2.8 EX DG Fisheye is a prime lens with fixed focal lenght of 15mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 22.5mm.
