He does let me borrow his lenses. He has the EF 24-105 f/4L and EF 70-300mm f/4.5-5.6 DO lenses, so if I were to 'complete' his arsenal with my own input, it'd be the 17-40mm one. However, I plan on going abroad for several months next year, so I doubt he would let me borrow them for such a long time.