I have a 5D and a 24-105mm f4. I need a wide or super wide angle lens to do architectural photos including some high rise buildings. I did some reserches that I need a tilt-shift lens. But canon t/s 17mm is over my budget at this moment. please recommand good lenses. also, just wondering if that is possible not using tilt-shift lenses and still doing a good job? Many thanks!