The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 28-70mm F3.5-5.6 II and the Tamron 17-70 F2.8 Di III-A VC 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. 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 II 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 the Sony FE 28-70mm F3.5-5.6 II'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. Sony FE 28-70mm F3.5-5.6 II weighs 295g, which means it is 230g (43%) lighter than the Tamron 17-70 F2.8 Di III-A VC which has a 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 Lenses in Sony E Mount for Size Comparison
Filter Threads
The Sony FE 28-70mm F3.5-5.6 II has a filter size of 55mm whereas the Tamron 17-70 F2.8 Di III-A VC has a 67mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 55mm filters that we recommend you to consider for the Sony FE 28-70mm F3.5-5.6 II:
And these are the 67mm filters that we recommend for the Tamron 17-70 F2.8 Di III-A VC:
Lens Mounts
Both the Sony FE 28-70mm F3.5-5.6 II and the Tamron 17-70 F2.8 Di III-A VC has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony FX5, Sony A7R VI and Sony A7 V.
Tamron 17-70 F2.8 Di III-A VC is also available in Fujifilm X mount.
Focal Range
Sony FE 28-70mm F3.5-5.6 II 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 a 35mm (FF) equivalent of
42 - 105mm.
On the other hand, the 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.
