The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tokina 12-24mm f4 DX II and the Sigma 20mm F1.8 EX DG RF for their suitability to various photography scenarios:
Size and Weight Comparison
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 20mm F1.8 EX DG RF weighs 520g, 3% (20g) lighter than the Tokina 12-24mm f4 DX II's weight of 540g.
Filter Threads
The Tokina 12-24mm f4 DX II has a filter size of 77mm whereas the Sigma 20mm F1.8 EX DG RF has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 77mm filters that we recommend you to consider for the Tokina 12-24mm f4 DX II:
And these are the 82mm filters that we recommend for the Sigma 20mm F1.8 EX DG RF:
Lens Mounts
Both the Tokina 12-24mm f4 DX II and the Sigma 20mm F1.8 EX DG RF has the same Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (DX) lenses are Nikon D3500, Nikon D7500 and Nikon D5600.
Tokina 12-24mm f4 DX II is also available in the Canon EF mount.
Sigma 20mm F1.8 EX DG RF is also available in Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Focal Range
Tokina 12-24mm f4 DX II has a focal range of 12-24mm and
2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
18-36mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 20mm F1.8 EX DG RF is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 30mm.
