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 Sigma 18-50mm F2.8 DC 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 28-70mm F3.5-5.6 II is the longer of the two lenses at 83mm. The Sigma 18-50mm F2.8 DC DN C with a length of 75mm, is 8mm shorter. Besides being longer, the Sony FE 28-70mm F3.5-5.6 II also has a larger diameter of 73mm compared to the Sigma 18-50mm F2.8 DC DN C's 65mm 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. Sigma 18-50mm F2.8 DC DN C weighs 290g, 1% (5g) lighter than the Sony FE 28-70mm F3.5-5.6 II's weight of 295g.
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 Sony FE 28-70mm F3.5-5.6 II and the Sigma 18-50mm F2.8 DC DN C have the same Filter thread size of 55mm.
Below are links to the 55mm filters that we recommend you to consider for these lenses:
Lens Mounts
Both the Sony FE 28-70mm F3.5-5.6 II and the Sigma 18-50mm F2.8 DC 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 FX5, Sony A7R VI and Sony A7 V.
Sigma 18-50mm F2.8 DC DN C is also available in Leica L and Fujifilm X mounts.
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 Sigma 18-50mm F2.8 DC DN C has a focal range of 18-50mm and 2.8X zoom ratio which has an effective (full-frame 35mm equivalent) focal range of 27-75mm when used on a APS-C / DX format camera.
