Nothing wrong with 16-35 option. However 11-16 is usable on 5D's. You get f2.8 @ 15-16mm. Some vignetting @ 15 with circular occlusion at wider angles. Question becomes a choice wider on 7D ( I have ) or usable 5D @ 16mm f2.8... do I hear a crop in here? 18 or 21 mp your choice. Nothing wrong with the 10-22 either. Check out Kenrockwell, Canon Digital Photography Forums and others for the facts.