The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Carl Zeiss Distagon T3,5/18 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 T3,5/18 with a length of 84mm, is 46mm 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 T3,5/18's 87mm 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 T3,5/18 weighs 470g, which means it is 480g (50%) lighter than the Sigma 20mm F1.4 DG HSM A which has a weight of 950g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Canon EF Mount for size comparison purposes.
Ultra-Wideangle Lenses in Canon EF Mount for Size Comparison
Lens Mounts
Both the Carl Zeiss Distagon T3,5/18 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 T3,5/18 is also available in Pentax KAF and Nikon F (FX) mounts.
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 T3,5/18 is a prime lens with fixed focal lenght of 18mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
28.8mm.
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.