The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang 16mm f2.0 and the Sigma 15mm F2.8 EX DG Fisheye 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. Samyang 16mm f2.0 is the longer of the two lenses at 89mm. The Sigma 15mm F2.8 EX DG Fisheye with a length of 65mm, is 24mm shorter. Besides being longer, the Samyang 16mm f2.0 also has a larger diameter of 83mm compared to the Sigma 15mm F2.8 EX DG Fisheye's 74mm 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. Sigma 15mm F2.8 EX DG Fisheye weighs 370g, 36% (213g) lighter than the Samyang 16mm f2.0's weight of 583g.
Lens Mounts
Both the Samyang 16mm f2.0 and the Sigma 15mm F2.8 EX DG Fisheye has the same Sony Alpha lens mount. Some of the latest released cameras that are compatible with the Sony Alpha lenses are Sony A68, Sony A77 II and Sony A58.
Samyang 16mm f2.0 is also available in Canon EF , Canon EF-M, Fujifilm X, Nikon F (DX), Four Thirds, Micro Four Thirds, Pentax KAF, Sony E and Samsung NX mounts.
Sigma 15mm F2.8 EX DG Fisheye is also available in Canon EF , Nikon F (FX), Pentax KAF and Sigma SA mounts.
Focal Range
Samyang 16mm f2.0 is a prime lens with fixed focal lenght of 16mm which has an effective (full-frame 35mm equivalent) focal range of
24mm when used on a APS-C / DX format camera.
On the other hand, the 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.