We’ve heard some chatter that Canon would continue to develop it’s non-L zoom lenses for full frame camera lineup and this patent for an EF 17-35mm f/4-5. 6 IS would seem to fit into that segment.
Canon News, a new leader in patent tracking found this one. Canon EF 17-35mm f/4-5. 6 IS STM Optical Formula Focal Read more. . . . canonrumors.com