The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 14-24mm F2.8 DG HSM and the Samyang 20mm F1.8 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. Sigma 14-24mm F2.8 DG HSM is the longer of the two lenses at 135mm. The Samyang 20mm F1.8 with a length of 88mm, is 47mm shorter. Besides being longer, the Sigma 14-24mm F2.8 DG HSM also has a larger diameter of 96mm compared to the Samyang 20mm F1.8's 83mm 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. Samyang 20mm F1.8 weighs 497g, 56% (653g) lighter than the Sigma 14-24mm F2.8 DG HSM's weight of 1150g.
Lens Mounts
Both the Sigma 14-24mm F2.8 DG HSM and the Samyang 20mm F1.8 has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K.
Sigma 14-24mm F2.8 DG HSM is also available in the Nikon F (FX) and Sigma SA mounts.
Samyang 20mm F1.8 is also available in Canon EF-M , Fujifilm X, Micro Four Thirds, Nikon F (FX), Pentax KAF, Samsung NX, Sony Alpha and Sony E mounts.
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 1.6x crop, it provides a 35mm (FF) equivalent of
22.4 - 38.4mm.
On the other hand, the Samyang 20mm F1.8 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 32mm.