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 Sigma 4.5mm F2.8 EX DC HSM 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. Sigma 4.5mm F2.8 EX DC HSM Fisheye is the longer of the two lenses at 78mm. The Canon 10-18mm f4.5-5.6 IS STM with a length of 72mm, is 6mm shorter. Besides being longer, the Sigma 4.5mm F2.8 EX DC HSM Fisheye also has a larger diameter of 76mm compared to the Canon 10-18mm f4.5-5.6 IS STM'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. Canon 10-18mm f4.5-5.6 IS STM weighs 240g, which means it is 230g (48%) lighter than the Sigma 4.5mm F2.8 EX DC HSM Fisheye which has a weight of 470g.
Lens Mounts
The Canon 10-18mm f4.5-5.6 IS STM has the Canon EF-S lens mount whereas the Sigma 4.5mm F2.8 EX DC HSM 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.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in Sigma SA and Nikon F (DX) 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 Sigma 4.5mm F2.8 EX DC HSM Fisheye is a prime lens with fixed focal lenght of 5mm which has an effective (full-frame 35mm equivalent) focal range of 8mm when used on a APS-C / DX format camera.
