The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 20-40mm F2.8 VXD and the Sony 12-24mm F2.8 GM 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 12-24mm F2.8 GM is the longer of the two lenses at 137mm. The Tamron 20-40mm F2.8 VXD with a length of 86mm, is 51mm shorter. Besides being longer, the Sony 12-24mm F2.8 GM also has a larger diameter of 98mm compared to the Tamron 20-40mm F2.8 VXD's 74mm diameter.
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Below you can find a scaled side-by-side image of Tamron 20-40mm F2.8 VXD and Sony 12-24mm F2.8 GM 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 20-40mm F2.8 VXD weighs 365g, which means it is 482g (56%) lighter than the Sony 12-24mm F2.8 GM which has a weight of 847g.
Lens Mounts
Both the Tamron 20-40mm F2.8 VXD and the Sony 12-24mm F2.8 GM 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
Tamron 20-40mm F2.8 VXD has a focal range of 20-40mm and
2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
30 - 60mm.
On the other hand, the Sony 12-24mm F2.8 GM has a focal range of 12-24mm and 2.0X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 18 - 36mm.