The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 50mm F1.4 DG HSM A and the Sigma 30mm F1.4 EX DC HSM 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 50mm F1.4 DG HSM A is the longer of the two lenses at 100mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 41mm shorter. Besides being longer, the Sigma 50mm F1.4 DG HSM A also has a larger diameter of 85mm compared to the Sigma 30mm F1.4 EX DC HSM's 77mm diameter.
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. Sigma 30mm F1.4 EX DC HSM weighs 430g, 47% (385g) lighter than the Sigma 50mm F1.4 DG HSM A's weight of 815g.
Below you can find the dimension and weight table of the Standard Prime Lenses in Sigma SA Mount for size comparison purposes.
Standard Prime Lenses in Sigma SA Mount for Size Comparison
Lens Mounts
Both the Sigma 50mm F1.4 DG HSM A and the Sigma 30mm F1.4 EX DC HSM has the same Sigma SA lens mount. Some of the latest released cameras that are compatible with the Sigma SA lenses are Sigma Quattro, Sigma Quattro H and Sigma SD1 Merrill.
Sigma 50mm F1.4 DG HSM A is also available in Canon EF , Sony Alpha, Nikon F (FX) and Leica L mounts.
Sigma 30mm F1.4 EX DC HSM is also available in Canon EF-S , Nikon F (DX), Four Thirds, Pentax KAF and Sony Alpha mounts.
Focal Range
Sigma 50mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 50mm. Sigma 30mm F1.4 EX DC HSM is a prime lens with fixed focal lenght of 30mm which has an effective (full-frame 35mm equivalent) focal range of 45mm when used on a APS-C / DX format camera.