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 Samyang 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. Samyang 8mm F3.5 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 Samyang 8mm F3.5 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 Samyang 8mm F3.5 Fisheye has the Canon EF 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 Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Samyang 8mm F3.5 Fisheye is also available in Nikon F (DX) , Four Thirds, Pentax KAF, Sony Alpha and Samsung NX mounts.
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 Samyang 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.
