The new Sigma lens is now in Stock at BHphoto. Adorama. Amazon. FocusCamera. Fotokoch DE. Erhardt DE. Calumet DE. WexUK.
Marc from SonyAlphaBlog tested the new Sigma lens and concluded:
The Sigma 16-28mm F2.8 DG DN provide a very good lens for a 24/33/42Mpix camera. Overall it is a bit better than the Tamron 17-28mm F2.8 Di III RXD : wider , more consistent from centre to corners and a little bit sharper at the wide position (16mm). If compactness and max sharpness are the most important for you then the Sony PZ 16-35mm F4 G will be the best choice (both in photo and in video). If you want the best one for 50/61Mpix sensor then stick to Sony FE 16-35 mm F2.8 GM or the Sony PZ 16-35mm F4 G