The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 35mm F1.8 Di VC USD 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 Tamron 35mm F1.8 Di VC USD 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 Tamron 35mm F1.8 Di VC USD's 80mm diameter.
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Below you can find a scaled side-by-side image of Tamron 35mm F1.8 Di VC USD and Sigma 20mm F1.4 DG HSM A to get a better idea of how their sizes compare in real life.
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. Tamron 35mm F1.8 Di VC USD weighs 480g, which means it is 470g (49%) lighter than the Sigma 20mm F1.4 DG HSM A which has a weight of 950g.
Lens Mounts
Both the Tamron 35mm F1.8 Di VC USD 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.
Tamron 35mm F1.8 Di VC USD is also available in Nikon F (FX) and Sony Alpha mounts.
Sigma 20mm F1.4 DG HSM A is also available in Nikon F (FX) , Sigma SA and Leica L mounts.
Focal Range
Tamron 35mm F1.8 Di VC USD is a prime lens with fixed focal lenght of 35mm. When it is mounted on an APS-C sensor camera with 1.6x crop, it provides a 35mm (FF) equivalent of
56mm.
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.