The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 8-16mm F4.5-5.6 DC HSM 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. Samyang 8mm F2.8 Fisheye weighs 265g, 52% (290g) lighter than the Sigma 8-16mm F4.5-5.6 DC HSM's weight of 555g.
Lens Mounts
The Sigma 8-16mm F4.5-5.6 DC HSM has the Canon EF lens mount whereas the Samyang 8mm F2.8 Fisheye has the Samsung NX lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount and Samsung NX1, Samsung NX3000 and Samsung NX30 for the Samsung NX Mount.
Sigma 8-16mm F4.5-5.6 DC HSM is also available in the Pentax KAF3 , Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Samyang 8mm F2.8 Fisheye is also available in Sony E mount.
Focal Range
Sigma 8-16mm F4.5-5.6 DC HSM has a focal range of 8-16mm and
2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
12.8-25.6mm 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.
