The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 24mm F1.4 DG HSM A and the Canon 20mm f2.8 USM for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Sigma 24mm F1.4 DG HSM A is the longer of the two lenses at 90mm. The Canon 20mm f2.8 USM with a length of 71mm is 19mm shorter. Besides being longer, the Sigma 24mm F1.4 DG HSM A also has a larger diameter of 85mm compared to Canon 20mm f2.8 USM's 78mm diameter.
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Canon 20mm f2.8 USM weighs 405g, 39% (260g) lighter than the Sigma 24mm F1.4 DG HSM A's weight of 665g.
Below you can find the dimension and weight table of the 'Wideangle Prime Lenses in Canon EF Mount for size comparison purposes.
Wideangle Prime Lenses in Canon EF Mount for Size Comparison
Both Sigma 24mm F1.4 DG HSM A and Canon 20mm f2.8 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 24mm F1.4 DG HSM A is also available in Nikon F (FX) , Sigma SA and Leica L mounts.
Sigma 24mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 24mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides an 35mm (FF) equivalent of 38.4mm.
Canon 20mm f2.8 USM 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 an 35mm (FF) equivalent of 32mm.