The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 8-16mm F4.5-5.6 DC HSM 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 8-16mm F4.5-5.6 DC HSM is the longer of the two lenses at 106mm. The Sigma 4.5mm F2.8 EX DC HSM Fisheye with a length of 78mm, is 28mm shorter. On the other hand, the Sigma 4.5mm F2.8 EX DC HSM Fisheye has a larger diameter of 76mm compared to the Sigma 8-16mm F4.5-5.6 DC HSM'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. Sigma 4.5mm F2.8 EX DC HSM Fisheye weighs 470g, 15% (85g) lighter than the Sigma 8-16mm F4.5-5.6 DC HSM's weight of 555g.
Lens Mounts
The Sigma 8-16mm F4.5-5.6 DC HSM has the Pentax KAF3 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 , and for the Pentax KAF3 Mount and Canon T8i, Canon 90D and Canon SL3 for the Canon EF Mount.
Sigma 8-16mm F4.5-5.6 DC HSM is also available in the Canon EF , Sony Alpha, Sigma SA and Nikon F (DX) mounts.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in Sigma SA and Nikon F (DX) mounts.
Focal Range
Sigma 8-16mm F4.5-5.6 DC HSM has a focal range of 8-16mm and
2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of
12-24mm 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.
