The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Kamlan 8mm F3.0 Fisheye and the Venus 9mm F2.8 Zero-D 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. Venus 9mm F2.8 Zero-D weighs 215g, 12% (30g) lighter than the Kamlan 8mm F3.0 Fisheye's weight of 245g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Sony E Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Kamlan 8mm F3.0 Fisheye and the Venus 9mm F2.8 Zero-D has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A6700, Sony FX30 and Sony ZV-E10.
Kamlan 8mm F3.0 Fisheye is also available in Canon EF-M mount.
Venus 9mm F2.8 Zero-D is also available in Canon EF-M and Fujifilm X mounts.
Focal Range
Kamlan 8mm F3.0 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.