The TS-E 17mm f/4L is a perspective control ultra-wide-angle lens designed to address the need for broader angles of view in architectural photography and similar fields. In addition to its superb optical performance — achieved through the use of a precision glass-molded aspherical element for the front element along with four UD elements, the TS-E 17mm f/4L features a special sub-wavelength structure coating (SWC) that substantially cuts flare and ghosting caused by light rays at a large angle of incidence. The floating construction corrects aberrations at short focusing distances, resulting in better image quality even at the image edges. We also added two new features — TS rotation, which allows the user to set the angle between the tilt and shift anywhere between orthogonal and parallel, and tilt lock, which securely locks the tilt mechanism in the neutral position — while aiming to make the lens more comfortable to operate by using larger control switches than previous TS-E models.