The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 20mm F1.4 DG HSM A and the Canon 28mm f1.8 USM 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 20mm F1.4 DG HSM A is the longer of the two lenses at 130mm. The Canon 28mm f1.8 USM with a length of 56mm, is 74mm shorter. Besides being longer, the Sigma 20mm F1.4 DG HSM A also has a larger diameter of 91mm compared to the Canon 28mm f1.8 USM's 74mm 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 28mm f1.8 USM weighs 310g, 67% (640g) lighter than the Sigma 20mm F1.4 DG HSM A's weight of 950g.
Lens Mounts
Both the Sigma 20mm F1.4 DG HSM A and the Canon 28mm f1.8 USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon 1D X III, Canon 6D MII and Canon 5D MIV.
Sigma 20mm F1.4 DG HSM A is also available in Nikon F (FX) , Sigma SA and Leica L mounts.
Focal Range
Sigma 20mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
32mm.
On the other hand, the Canon 28mm f1.8 USM is a prime lens with fixed focal lenght of 28mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 44.8mm.