According to TOKINA official web site about the Tokina AT-X 17-35mm f4 will be released delayed one month to the end of Aug.
When its official samples were released a few week ago, it pretty impressed me by its optical quality at the four edges of a image. Over 12 years ago, Tokina produced a series of AT-X PRO lenses which had a significant improvement of optical quality, especially the 28-70mm f2.6-2.8, The one got the optic design from a french brand, Angenieux. After ten year later, hopefully this full frame format lens will create another myth again, It is worth to wait.