Google plus user Peter Norvig posted a new low resolution image, the lens in the image is a new Canon EF lens that haven’t seen before, according to CR, this lens is not the 28-300L, 100-400L and 70-200L. So this new lens could be the rumored EF 100-400mm f/4.5-5.6L IS II USM lens.
For Canon fans, you might find this exciting. A photographer was using this lens. I assert that the black stripes of the focus and zoom rings are the wrong width and placement to be either the 70-200 or the 100-400; therefore I speculate this is a prototype of the long-rumored 100-400 II.