The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 17-70 F2.8 Di III-A VC and the Sony FE 28-70mm F3.5-5.6 OSS for their suitability to various photography scenarios:
Size and Weight Comparison
Size of a lens is an important deciding factor when comparing two lenses.Tamron 17-70 F2.8 Di III-A VC is the longer of the two lenses at 119mm. The Sony FE 28-70mm F3.5-5.6 OSS with a length of 83mm is 36mm shorter. Besides being longer, the Tamron 17-70 F2.8 Di III-A VC also has a larger diameter of 75mm compared to Sony FE 28-70mm F3.5-5.6 OSS's 73mm diameter.
Below you can find the scaled side by side image of Tamron 17-70 F2.8 Di III-A VC and Sony FE 28-70mm F3.5-5.6 OSS to get a better idea of how their size compare in real life.
Comparison image of Tamron 17-70 F2.8 Di III-A VC and Sony FE 28-70mm F3.5-5.6 OSS Size and Weight 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. Sony FE 28-70mm F3.5-5.6 OSS weighs 295g, 43% (230g) lighter than the Tamron 17-70 F2.8 Di III-A VC's weight of 525g.
Below you can find the dimension and weight table of the 'Standard Zoom Lenses in Sony E Mount for size comparison purposes.
Standard Zoom Lenses in Sony E Mount for Size Comparison
Lens Mounts
Both Tamron 17-70 F2.8 Di III-A VC and Sony FE 28-70mm F3.5-5.6 OSS has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX30, Sony ZV-E10 and Sony A6600.
Tamron 17-70 F2.8 Di III-A VC is also available in Fujifilm X mount.
Focal Range
Tamron 17-70 F2.8 Di III-A VC has a focal range of 17-70mm and 4.1X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 25.5-105mm when used on a APS-C / DX format camera. Sony FE 28-70mm F3.5-5.6 OSS has a focal range of 28-70mm and 2.5X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides an 35mm (FF) equivalent of 42 - 105mm.