I am moving out to Denver this next month and i want to get into some landscape photography. I know nothing about wide angle lenses. I would like to stay in the canon range but im not opposed to 3rd party lense as long as there good quality. Im leaning towards the 24-70 because of the versatility, but im worried that because i have a crop frame camera so the equivalent of 38mm is to narrow. EF 17-40mm f/4L USM EF 16-35mm f/2.8L USM EF 24-70mm f/2.8L USM are there any else that im forgetting?