UPDATED 24 Sep 2021: It looks like Sigma’s next release could be the Sigma 18-50mm f/2.8 DC DN Contemporary lens for Sony APS-C cameras. If the rumor is true, it will be the first zoom lens for cropped sensor, Sony E mount cameras that Sigma has made.
The Sigma 18-50mm f/2.8 DC DN will be the equivalent of shooting a 27-75mm lens on a full-frame camera, thanks to the 1.5x crop factor of APS-C sensors. Paired with something like the Sony A6400, it could be the perfect solution for travel photographers and portrait photographers alike.
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Leaked specs from ever-reliable outlet Nokishita suggest it will be made up of 13 elements in 10 groups, have a minimum shooting distance of 12.1cm at the wide-angle and 30cm at the telephoto end. It's set to be a small, lightweight lens weighing only 290g, with a diameter of 61.6x76.5mm.
This versatile, fast zoom is likely to be a welcome addition to the Sony APS-C market, if the build quality and autofocus speed are anything similar to that of the Sigma 28-70mm f/2.8 DG DN Contemporary lens for Sony FE mount. When the Sigma 28-70mm was released, it gave Sony full-frame users the opportunity to buy a standard zoom lens at f/2.8 for under a grand.
If the 18-50mm does go to market, as claimed by Nokishita on Twitter, it could be contending against the Sony E 16-55 f/2.8 G and the Tamron 17-70mm f/2.8 Di III-A VC RXD. There has been no mention yet of its specs, price, or an official release date, but it would be reasonable to expect its starting price tag to be around the same as the Tamron 17-70mm, based on the price difference between the Sigma 28-70mm and the Tamron 28-75mm Di III RXD.
Since Sigma released its line of Art and Contemporary lenses, it’s become a popular choice for photographers looking for high-quality optics at more affordable prices than manufacturer's own-brand lenses. News that there could be another mid-range zoom option on the horizon should be an exciting prospect for Sony APS-C shooters.