The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Viltrox AF 56mm f1.7 XF and the Sigma 8mm F3.5 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. Sigma 8mm F3.5 EX DG Fisheye is the longer of the two lenses at 69mm. The Viltrox AF 56mm f1.7 XF with a length of 55mm, is 14mm shorter. Besides being longer, the Sigma 8mm F3.5 EX DG Fisheye also has a larger diameter of 74mm compared to the Viltrox AF 56mm f1.7 XF's 65mm 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. Viltrox AF 56mm f1.7 XF weighs 171g, which means it is 229g (57%) lighter than the Sigma 8mm F3.5 EX DG Fisheye which has a weight of 400g.
Lens Mounts
The Viltrox AF 56mm f1.7 XF has the Fujifilm X lens mount whereas the Sigma 8mm F3.5 EX DG Fisheye has the Canon EF lens mount. Some of the latest released cameras that are compatible with these mounts are Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount and Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K for the Canon EF Mount.
Sigma 8mm F3.5 EX DG Fisheye is also available in Nikon F (FX) and Sigma SA mounts.
Focal Range
Viltrox AF 56mm f1.7 XF is a prime lens with fixed focal lenght of 56mm which has an effective (full-frame 35mm equivalent) focal range of
84mm when used on a APS-C / DX format camera.
On the other hand, the Sigma 8mm F3.5 EX DG Fisheye is a prime lens with fixed focal lenght of 8mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 12.8mm.
