The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sigma 28mm 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 28mm F1.4 DG HSM A is the longer of the two lenses at 108mm. The Sigma 30mm F1.4 EX DC HSM with a length of 59mm, is 49mm shorter. Besides being longer, the Sigma 28mm F1.4 DG HSM A also has a larger diameter of 83mm 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.
Lens Mounts
Both the Sigma 28mm 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 28mm F1.4 DG HSM A is also available in Canon EF , Nikon F (FX), Sony E 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 28mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 28mm. 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.