The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 14mm F1.8 GM and the Tamron 20mm F2.8 Di III OSD M1:2 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. Sony FE 14mm F1.8 GM is the longer of the two lenses at 100mm. The Tamron 20mm F2.8 Di III OSD M1:2 with a length of 64mm, is 36mm shorter. Besides being longer, the Sony FE 14mm F1.8 GM also has a larger diameter of 83mm compared to the Tamron 20mm F2.8 Di III OSD M1:2'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. Tamron 20mm F2.8 Di III OSD M1:2 weighs 220g, 52% (240g) lighter than the Sony FE 14mm F1.8 GM's weight of 460g.
Below you can find the dimension and weight table of the Wideangle Prime Lenses in Sony E Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Sony FE 14mm F1.8 GM and the Tamron 20mm F2.8 Di III OSD M1:2 has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A9 III, Sony A7C Mark II and Sony A7CR.
Focal Range
Sony FE 14mm F1.8 GM is a prime lens with fixed focal lenght of 14mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
21mm.
On the other hand, the Tamron 20mm F2.8 Di III OSD M1:2 is a prime lens with fixed focal lenght of 20mm. When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 30mm.