The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Rokinon 8mm f3.5 Fisheye and the Sigma 24-70mm F2.8 II 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. Sigma 24-70mm F2.8 II is the longer of the two lenses at 122mm. The Rokinon 8mm f3.5 Fisheye with a length of 77mm, is 45mm shorter. Besides being longer, the Sigma 24-70mm F2.8 II also has a larger diameter of 88mm compared to the Rokinon 8mm f3.5 Fisheye's 75mm 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. Rokinon 8mm f3.5 Fisheye weighs 443g, which means it is 292g (39%) lighter than the Sigma 24-70mm F2.8 II which has a weight of 735g.
Lens Mounts
The Rokinon 8mm f3.5 Fisheye has the Samsung NX lens mount whereas the Sigma 24-70mm F2.8 II has the Sony E lens mount. Some of the latest released cameras that are compatible with these mounts are Samsung NX1, Samsung NX3000 and Samsung NX30 for the Samsung NX Mount and Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount.
Rokinon 8mm f3.5 Fisheye is also available in the Canon EF , Nikon F (FX), Four Thirds, Pentax KAF and Sony Alpha mounts.
Sigma 24-70mm F2.8 II is also available in Leica L mount.
Focal Range
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.
On the other hand, the Sigma 24-70mm F2.8 II has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 36 - 105mm.
