The Tokina AT-X 17-35mm f/4 Pro FX is a new constant-aperture wide zoom lens for 35mm full-frame SLR cameras. Available in Canon and Nikon fit, from July and September respectively, the Tokina AT-X 17-35mm f/4 Pro FX has an optical formula that comprises 13 elements arranged in 12 groups, and comes with a nine-bladed iris diaphragm. Notable features include an angle-of-view range of 103.96° -64.74°, a rubber seal around the lens mount, and Tokina’s exclusive one-tocuh focus clutch mechanism that allows the photographer to switch between AF and MF simply by snapping the focus ring forward for AF and back toward the camera to focus manually. Both the Canon and the Nikon versions come with a silent, high-precision AF motor, just like the bigger and faster AT-X 16-35mm f/2.8 Pro FX (read review). The Tokina AT-X 17-35mm f/4 Pro FX lens will be available for 98,000 yen in Japan, including a hood. Currently, there is no word on international availability or pricing.