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 Canon 15mm f2.8 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 Canon 15mm f2.8 Fisheye with a length of 62mm, is 15mm shorter. Besides being longer, the Rokinon 8mm f3.5 Fisheye also has a larger diameter of 75mm compared to the Canon 15mm f2.8 Fisheye's 73mm 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. Canon 15mm f2.8 Fisheye weighs 330g, 25% (113g) lighter than the Rokinon 8mm f3.5 Fisheye's weight of 443g.
Below you can find the dimension and weight table of the Wideangle Fisheye Prime Lenses in Canon EF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Rokinon 8mm f3.5 Fisheye and the Canon 15mm f2.8 Fisheye has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon T8i, Canon 90D and Canon SL3.
Rokinon 8mm f3.5 Fisheye is also available in the Nikon F (FX) , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
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
12.8mm when used on a APS-C / DX format camera.
On the other hand, the Canon 15mm f2.8 Fisheye is a prime lens with fixed focal lenght of 15mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 24mm.
