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 Rokinon 8mm f3.5 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. Rokinon 8mm f3.5 Fisheye is the longer of the two lenses at 77mm. The Sigma 15mm F2.8 EX DG Fisheye with a length of 65mm, is 12mm shorter. Besides being longer, the Rokinon 8mm f3.5 Fisheye also has a larger diameter of 75mm 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, which means it is 73g (16%) lighter than the Rokinon 8mm f3.5 Fisheye which has a weight of 443g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Nikon F (FX) Mount for size comparison purposes.
Ultra-Wideangle Lenses in Nikon F (FX) Mount for Size Comparison
Lens Mounts
Both the Sigma 15mm F2.8 EX DG Fisheye and the Rokinon 8mm f3.5 Fisheye has the same Nikon F (FX) lens mount. Some of the latest released cameras that are compatible with the Nikon F (FX) lenses are Nikon D6, Nikon D780 and Nikon D3500.
Sigma 15mm F2.8 EX DG Fisheye is also available in the Canon EF , Pentax KAF, Sony Alpha and Sigma SA mounts.
Rokinon 8mm f3.5 Fisheye is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
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 Rokinon 8mm f3.5 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.
