The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 8mm f2.8 Fisheye and the Venus 9mm F2.8 Zero-D 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. Rokinon 8mm f2.8 Fisheye is the longer of the two lenses at 77mm. The Venus 9mm F2.8 Zero-D with a length of 53mm, is 24mm shorter. Besides being longer, the Rokinon 8mm f2.8 Fisheye also has a larger diameter of 75mm compared to the Venus 9mm F2.8 Zero-D's 60mm 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. Venus 9mm F2.8 Zero-D weighs 215g, 51% (228g) lighter than the Rokinon 8mm f2.8 Fisheye's weight of 443g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Fujifilm X Mount for size comparison purposes.
Ultra-Wideangle Lenses in Fujifilm X Mount for Size Comparison
Lens Mounts
Both the Rokinon 8mm f2.8 Fisheye and the Venus 9mm F2.8 Zero-D has the same Fujifilm X lens mount. Some of the latest released cameras that are compatible with the Fujifilm X lenses are Fujifilm X-S20, Fujifilm X-T5 and Fujifilm X-H2.
Venus 9mm F2.8 Zero-D is also available in Canon EF-M and Sony E mounts.
Focal Range
Rokinon 8mm f2.8 Fisheye is a prime lens with fixed focal lenght of 8mm which has an effective (full-frame 35mm equivalent) focal range of
12mm when used on a APS-C / DX format camera.
On the other hand, the Venus 9mm F2.8 Zero-D 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.