Since 1.6x camera bodies do not need all of the image this lens presents, a more-light-reducing lens hood can be used. Friends of the site have reported that the Canon EF 24mm f/1.4L Lens' EW-83DII lens hood and the Canon EF 24-105mm f/4L IS Lens' EW-83H work well as alternatives for these bodies. I tested the EW-83J from the Canon EF-S 17-55mm f/2.8 IS Lens and it seems to work fine on the 17-40. It fits and does not cause vignetting at 17mm and f/4. It looks a lot better as well.
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Canon EF 17-40mm f/4L USM Lens Review
Sam używałem którejś z nich (chyba tej ostatniej - oczywiście zamiennika) i było ok.