A good alternative, but not EF-S mount. Only Canon make EF-S mount lenses. It will fit on a full frame body, but you will probably get pretty severe vignetting on FF bodies.A nice alternative to the Canon 17-55mm, if you dont want to blow the budget, is the Tamron 17-50mm f/2.8. It lacks IS, is a few mm shorter and unfortunately comes in EF-S mount only. But at least you'll save yourself around R5000 that you could put to better use once you decide to go FF. It gets pretty good reviews.