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 Sigma 10-20mm F4-5.6 EX DC HSM 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 Sigma 10-20mm F4-5.6 EX DC HSM with a length of 81mm, is 49mm shorter. Besides being longer, the Sigma 20mm F1.4 DG HSM A also has a larger diameter of 91mm compared to the Sigma 10-20mm F4-5.6 EX DC HSM's 84mm 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. Sigma 10-20mm F4-5.6 EX DC HSM weighs 470g, 50% (480g) 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 Sigma 10-20mm F4-5.6 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 20mm F1.4 DG HSM A is also available in the Canon EF , Nikon F (FX) and Leica L mounts.
Sigma 10-20mm F4-5.6 EX DC HSM is also available in Canon EF , Four Thirds, Pentax KAF, Sony Alpha and Nikon F (DX) mounts.
Focal Range
Sigma 20mm F1.4 DG HSM A is a prime lens with fixed focal lenght of 20mm.
On the other hand, the Sigma 10-20mm F4-5.6 EX DC HSM has a focal range of 10-20mm and 2.0X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 15-30mm when used on a APS-C / DX format camera.
