The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Samyang AF 14mm F2.8 EF 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. Samyang AF 14mm F2.8 EF is the longer of the two lenses at 96mm. The Sigma 4.5mm F2.8 EX DC HSM Fisheye with a length of 78mm, is 18mm shorter. Besides being longer, the Samyang AF 14mm F2.8 EF also has a larger diameter of 91mm compared to the Sigma 4.5mm F2.8 EX DC HSM Fisheye's 76mm 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, 3% (15g) lighter than the Samyang AF 14mm F2.8 EF's weight of 485g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Canon EF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Samyang AF 14mm F2.8 EF and the Sigma 4.5mm F2.8 EX DC HSM Fisheye has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Blackmagic URSA 12K LF, Z CAM E2-F6 II 6K and Z CAM E2-S6 II 6K.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in Sigma SA and Nikon F (DX) mounts.
Focal Range
Samyang AF 14mm F2.8 EF is a prime lens with fixed focal lenght of 14mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
22.4mm.
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.