The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Viltrox 9mm F2.8 X 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 9mm F2.8 X with a length of 56mm, is 13mm shorter. Besides being longer, the Sigma 8mm F3.5 EX DG Fisheye also has a larger diameter of 74mm compared to the Viltrox 9mm F2.8 X'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 9mm F2.8 X weighs 175g, which means it is 225g (56%) lighter than the Sigma 8mm F3.5 EX DG Fisheye which has a weight of 400g.
Lens Mounts
The Viltrox 9mm F2.8 X has the Fujiflm X lens mount whereas the Sigma 8mm F3.5 EX DG Fisheye has the Sigma SA 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 Fujiflm X Mount and Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill for the Sigma SA Mount.
Sigma 8mm F3.5 EX DG Fisheye is also available in Canon EF and Nikon F (FX) mounts.
Focal Range
Viltrox 9mm F2.8 X is a prime lens with fixed focal lenght of 9mm which has an effective (full-frame 35mm equivalent) focal range of
13.5mm 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.
