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 Sigma 24-70 F2.8 DG DN Art 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. Sigma 24-70 F2.8 DG DN Art is the longer of the two lenses at 123mm. The Tamron 17-70 F2.8 Di III-A VC with a length of 119mm, is 4mm shorter. Besides being longer, the Sigma 24-70 F2.8 DG DN Art also has a larger diameter of 88mm compared to the Tamron 17-70 F2.8 Di III-A VC's 75mm diameter.
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Below you can find a scaled side-by-side image of Tamron 17-70 F2.8 Di III-A VC and Sigma 24-70 F2.8 DG DN Art 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 17-70 F2.8 Di III-A VC weighs 525g, which means it is 310g (37%) lighter than the Sigma 24-70 F2.8 DG DN Art which has a weight of 835g.
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 Tamron 17-70 F2.8 Di III-A VC has a filter size of 67mm whereas the Sigma 24-70 F2.8 DG DN Art has a 82mm diameter. Larger filters are generally more expensive than the smaller ones given all the other features are equal.
Below are links to the 67mm filters that we recommend you to consider for the Tamron 17-70 F2.8 Di III-A VC:
And these are the 82mm filters that we recommend for the Sigma 24-70 F2.8 DG DN Art:
Lens Mounts
Both the Tamron 17-70 F2.8 Di III-A VC and the Sigma 24-70 F2.8 DG DN Art has the same Sony E lens mount. Some of the latest released cameras that are compatible with the Sony E lenses are Sony A6700, Sony FX30 and Sony ZV-E10.
Tamron 17-70 F2.8 Di III-A VC is also available in Fujifilm X mount.
Sigma 24-70 F2.8 DG DN Art is also available in Leica L 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.
On the other hand, the Sigma 24-70 F2.8 DG DN Art has a focal range of 24-70mm and 2.9X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of 36 - 105mm.