The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 24-70 F2.8 DG DN Art 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 24-70 F2.8 DG DN Art is the longer of the two lenses at 123mm. The Sigma 4.5mm F2.8 EX DC HSM Fisheye with a length of 78mm, is 45mm shorter. Besides being longer, the Sigma 24-70 F2.8 DG DN Art also has a larger diameter of 88mm 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, 43% (365g) lighter than the Sigma 24-70 F2.8 DG DN Art's weight of 835g.
Lens Mounts
The Sigma 24-70 F2.8 DG DN Art has the Sony E lens mount whereas the Sigma 4.5mm F2.8 EX DC HSM Fisheye has the Nikon F (DX) lens mount. Some of the latest released cameras that are compatible with these mounts are Sony FX5, Sony A7R VI and Sony A7 V for the Sony E Mount and Nikon D3500, Nikon D7500 and Nikon D5600 for the Nikon F (DX) Mount.
Sigma 24-70 F2.8 DG DN Art is also available in the Leica L mount.
Sigma 4.5mm F2.8 EX DC HSM Fisheye is also available in Canon EF and Sigma SA mounts.
Focal Range
Sigma 24-70 F2.8 DG DN Art has a focal range of 24-70mm and
2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
36 - 105mm.
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 7.5mm when used on a APS-C / DX format camera.
