The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 15mm F2.8 EX DG Fisheye 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, 28% (105g) lighter than the Sigma 15mm F2.8 EX DG Fisheye's weight of 370g.
Lens Mounts
The Sigma 15mm F2.8 EX DG Fisheye has the Pentax KAF lens mount whereas the Samyang 8mm F2.8 Fisheye has the Sony E lens mount. Some of the latest released cameras that are compatible with these mounts are Pentax K-3 III Mono, Pentax KF and Pentax K-3 III for the Pentax KAF Mount and Sony ZV-E10 II, Sony A6700 and Sony FX30 for the Sony E Mount.
Sigma 15mm F2.8 EX DG Fisheye is also available in the Canon EF , Nikon F (FX), Sony Alpha and Sigma SA mounts.
Samyang 8mm F2.8 Fisheye is also available in Samsung NX mount.
Focal Range
Sigma 15mm F2.8 EX DG Fisheye is a prime lens with fixed focal lenght of 15mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
22.5mm.
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.
