Because that is just a wide-angle lens adapter, not a wide angle lens. A wide-angle lens adapter is just some cheap crap that screws onto the filter threads of a lens, in that case, any lens with a 58mm filter thread size. If you want a wide-angle lens for your DSLR, you want an actual lens like this: http://www.amazon.com/Canon-EF-S-10-22mm-3-5-4-5-Digital/dp/B0002Y5WXE/ref=sr_1_1?ie=UTF8&qid=1310312030&sr=8-1 which isn't cheap, made by canon- or as an alternative, like this: http://www.amazon.com/Sigma-10-20mm-4-5-6-Digital-Cameras/dp/B0007U00X0/ref=sr_1_2?ie=UTF8&qid=1310312030&sr=8-2 which is cheaper but still over $400, made by sigma- both highly rated lenses.