The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 4.5mm F2.8 EX DC HSM Fisheye and the Canon 55-250mm f4-5.6 IS STM 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. Canon 55-250mm f4-5.6 IS STM is the longer of the two lenses at 111mm. The Sigma 4.5mm F2.8 EX DC HSM Fisheye with a length of 78mm, is 33mm shorter. On the other hand, the Sigma 4.5mm F2.8 EX DC HSM Fisheye has a larger diameter of 76mm compared to the Canon 55-250mm f4-5.6 IS STM's 70mm 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 55-250mm f4-5.6 IS STM weighs 375g, 20% (95g) lighter than the Sigma 4.5mm F2.8 EX DC HSM Fisheye's weight of 470g.
Lens Mounts
The Sigma 4.5mm F2.8 EX DC HSM Fisheye has the Canon EF lens mount whereas the Canon 55-250mm f4-5.6 IS STM has the Canon EF-S 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 Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF-S Mount.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in the Sigma SA and Nikon F (DX) mounts.
Focal Range
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.
On the other hand, the Canon 55-250mm f4-5.6 IS STM has a focal range of 55-250mm and 4.5X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 88-400mm when used on a APS-C / DX format camera.
