The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 30mm F1.4 DC HSM and the Canon 50mm f1.4 USM for their suitability to various photography scenarios:
Size and Weight Comparison
The size of a lens is an important deciding factor when comparing two lenses. Sigma 30mm F1.4 DC HSM is the longer of the two lenses at 63mm. The Canon 50mm f1.4 USM with a length of 51mm, is 12mm shorter. On the other hand, there is no difference between the max diameters of these lenses, both coming at 74mm.
The 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 50mm f1.4 USM weighs 290g, 33% (145g) lighter than the Sigma 30mm F1.4 DC HSM's weight of 435g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Canon EF Mount for size comparison purposes.
Standard Prime Lenses in Canon EF Mount for Size Comparison
Both the Sigma 30mm F1.4 DC HSM and the Canon 50mm f1.4 USM has the same Canon EF lens mount. Some of the latest released cameras that are compatible with the Canon EF lenses are Canon T8i, Canon 90D and Canon SL3.
Sigma 30mm F1.4 DC HSM is also available in Nikon F (DX) and Sigma SA mounts.
Sigma 30mm F1.4 DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of 48mm when used on a APS-C / DX format camera. Canon 50mm f1.4 USM is a prime lens with fixed focal lenght of 50mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of 80mm.