The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Canon 10-18mm f4.5-5.6 IS STM and the Rokinon 8mm 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 f2.8 Fisheye is the longer of the two lenses at 77mm. The Canon 10-18mm f4.5-5.6 IS STM with a length of 72mm, is 5mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 75mm.
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 10-18mm f4.5-5.6 IS STM weighs 240g, which means it is 203g (45%) lighter than the Rokinon 8mm f2.8 Fisheye which has a weight of 443g.
Lens Mounts
The Canon 10-18mm f4.5-5.6 IS STM has the Canon EF-S lens mount whereas the Rokinon 8mm f2.8 Fisheye has the Fujifilm X lens mount. Some of the latest released cameras that are compatible with these mounts are Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount and Fujifilm X-T30 III, Fujifilm X-E5 and Fujifilm X-M5 for the Fujifilm X Mount.
Focal Range
Canon 10-18mm f4.5-5.6 IS STM has a focal range of 10-18mm and
1.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
16-28.8mm when used on a APS-C / DX format camera.
On the other hand, the Rokinon 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.
