The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony 12-24mm F2.8 GM and the Tamron 17-28mm F2.8 Di III 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 17-28mm F2.8 Di III with a length of 99mm, is 38mm shorter. Besides being longer, the Sony 12-24mm F2.8 GM also has a larger diameter of 98mm compared to the Tamron 17-28mm F2.8 Di III's 73mm diameter.
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Below you can find a scaled side-by-side image of Sony 12-24mm F2.8 GM and Tamron 17-28mm F2.8 Di III 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 17-28mm F2.8 Di III weighs 420g, 50% (427g) lighter than the Sony 12-24mm F2.8 GM's weight of 847g.
Below you can find the dimension and weight table of the Wideangle Zoom Lenses in Sony E Mount for size comparison purposes.
Ultra-Wideangle Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both the Sony 12-24mm F2.8 GM and the Tamron 17-28mm F2.8 Di III 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 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.
On the other hand, the Tamron 17-28mm F2.8 Di III has a focal range of 17-28mm and 1.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 25.5 - 42mm.