The type of photography that you are planning to use is an important decision factor. Here we have evaluated the Sony FE 24-70mm F2.8 GM 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. Sony FE 24-70mm F2.8 GM is the longer of the two lenses at 136mm. The Sigma 28-70mm F2.8 DG DN C with a length of 102mm, is 34mm shorter. Besides being longer, the Sony FE 24-70mm F2.8 GM also has a larger diameter of 88mm 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 Sony FE 24-70mm F2.8 GM 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, 46% (416g) lighter than the Sony FE 24-70mm F2.8 GM's weight of 886g.
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 24-70mm F2.8 GM has a filter size of 82mm whereas the Sigma 28-70mm F2.8 DG DN C 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 82mm filters that we recommend you to consider for the Sony FE 24-70mm F2.8 GM:
And these are the 67mm filters that we recommend for the Sigma 28-70mm F2.8 DG DN C:
Lens Mounts
Both the Sony FE 24-70mm F2.8 GM 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
Sony FE 24-70mm F2.8 GM 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.
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.