The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Tamron 28-75mm F2.8 Di III and the Sigma 28-70mm F2.8 DG DN C 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 28-75mm F2.8 Di III is the longer of the two lenses at 117mm. The Sigma 28-70mm F2.8 DG DN C with a length of 102mm, is 15mm shorter. Besides being longer, the Tamron 28-75mm F2.8 Di III also has a larger diameter of 73mm compared to the Sigma 28-70mm F2.8 DG DN C's 72mm diameter.
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Below you can find a scaled side-by-side image of Tamron 28-75mm F2.8 Di III and Sigma 28-70mm F2.8 DG DN C 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. Sigma 28-70mm F2.8 DG DN C weighs 470g, 14% (80g) lighter than the Tamron 28-75mm F2.8 Di III's weight of 550g.
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
Both the Tamron 28-75mm F2.8 Di III and the Sigma 28-70mm F2.8 DG DN C have the same Filter thread size of 67mm.
Below are links to the 67mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Tamron 28-75mm F2.8 Di III and the Sigma 28-70mm F2.8 DG DN C 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.
Sigma 28-70mm F2.8 DG DN C is also available in Leica L mount.
Focal Range
Tamron 28-75mm F2.8 Di III has a focal range of 28-75mm and
2.7X zoom ratio . When it is mounted on an APS-C sensor camera with 1.5x crop, it provides a 35mm (FF) equivalent of
42 - 112.5mm.
On the other hand, the Sigma 28-70mm F2.8 DG DN C 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.