It was done by some 1D-series owners. Since the 1D series used APS-H sensors with a 1.3x crop factor, the ultrawide zooms for FF (16-35, 17-40) didn't give wider than 20mm on those bodies. Mounting a modified EF-S 10-22mm on a 1D body was usable from 12-13mm onward, giving a 16mm FF-equivalent FoV.