The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Carl Zeiss Distagon T2/25 and the Sigma 20mm F1.4 DG HSM A 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 Carl Zeiss Distagon T2/25 with a length of 98mm, is 32mm shorter. Besides being longer, the Sigma 20mm F1.4 DG HSM A also has a larger diameter of 91mm compared to the Carl Zeiss Distagon T2/25's 73mm 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. Carl Zeiss Distagon T2/25 weighs 600g, which means it is 350g (36%) lighter than the Sigma 20mm F1.4 DG HSM A which has a weight of 950g.
Lens Mounts
Both the Carl Zeiss Distagon T2/25 and the Sigma 20mm F1.4 DG HSM A 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.
Carl Zeiss Distagon T2/25 is also available in Nikon F (FX) mount.
Sigma 20mm F1.4 DG HSM A is also available in Nikon F (FX) , Sigma SA and Leica L mounts.
Focal Range
Carl Zeiss Distagon T2/25 is a prime lens with fixed focal lenght of 25mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
40mm.
On the other hand, the Sigma 20mm F1.4 DG HSM A 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 a 35mm (FF) equivalent of 32mm.