Sigma 28-70mm FE reviews by Ted Forbes, Dpreview, Photographyblog

Sigma 28-70mm at BHphoto. Adorama.

Photographyblog tested the new lens and concluded:

Overall, the new Sigma 28-70mm F2.8 DG DN Contemporary is a well-built, fast standard zoom lens that delivers excellent image quality in a very small, lightweight package.
It isn’t as good as our favourite full-frame standard zoom, the Sigma 28-70mm F2.8 DG DN, in any aspect except size, but it does out-perform its main rival, the Tamron 28-75mm F2.8 Di III RXD, albeit at a slightly higher price-point, which makes choosing between them a close-run thing.

Dpreview also reviewed the lens and concluded:

If what you need most of all is portability and you understand the compromises necessary to achieve it, the Sigma 28-70mm F2.8 DG DN is hands-down the smallest and lightest of the bunch and still offers solid image quality.
It doesn’t hurt that it’s also among the most affordable F2.8 full-frame standard zoom options for the E- or L-mounts. For the size, weight and cost-conscious, it’s definitely worthy of consideration.

And here is Ted Forbes take on the lens:

Crispy Quality. Sigma 35mm F2 DG DN Contemporary Review

ThePhoBlographer reviewed the Sigma lens and concluded:

The Sigma 35mm f2 DG DN Contemporary is an alright lens. It’s hard for me to get excited about something that’s not incredibly special. But if it’s your first 35mm lens, it’s a heck of an option. It’s fantastic for professional-grade work that doesn’t require rough and tumble. In controlled environments, the Sigma 35mm f2 DG DN Contemporary will really shine. However, the autofocus needs improvements. It could really use weather sealing. And there are a few other good options on the market if you’re using E mount. Overall, the Sigma 35mm f2 DG DN Contemporary is in kind of an awkward place. If it’s bundled as a kit lens with the Sigma FP, then that’s fine. Otherwise, there’s no reason to give it another look.