The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-28mm F2.8 Di III and the Sony FE 16-35mm F2.8 GM for their suitability to various photography scenarios:
Size and Weight Comparison
Weight of a lens is as important as its external dimensions, especially if you are planning to hand hold your camera and lens combination for longer periods. Tamron 17-28mm F2.8 Di III weighs 420g, which means it is 260g (38%) lighter than the Sony FE 16-35mm F2.8 GM which has a weight of 680g.
Below you can find the dimension and weight table of the 'Wideangle Zoom Lenses in Sony E Mount for size comparison purposes.
Wideangle Zoom Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both Tamron 17-28mm F2.8 Di III and Sony FE 16-35mm 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 A7R V, Sony FX30 and Sony A7 IV.
Focal Range
Tamron 17-28mm F2.8 Di III has a focal range of 17-28mm and 1.6X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 25.5 - 42mm.
Sony FE 16-35mm F2.8 GM has a focal range of 16-35mm and 2.2X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 24 - 52.5mm.