The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 10-18mm F2.8 DC DN C and the Samyang 8mm F2.8 Fisheye 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. Sigma 10-18mm F2.8 DC DN C weighs 255g, which means it is 10g (3%) lighter than the Samyang 8mm F2.8 Fisheye which has a weight of 265g.
Lens Mounts
Both the Sigma 10-18mm F2.8 DC DN C and the Samyang 8mm F2.8 Fisheye has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony ZV-E10 II, Sony A6700 and Sony FX30.
Sigma 10-18mm F2.8 DC DN C is also available in the Leica L , Fujifilm X and Canon RF mounts.
Samyang 8mm F2.8 Fisheye is also available in Samsung NX mount.
Focal Range
Sigma 10-18mm F2.8 DC DN C has a focal range of 10-18mm and
1.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
15-27mm when used on a APS-C / DX format camera.
On the other hand, the Samyang 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.