This is what the Sigma lens was made for, getting light and depth, all through out the 18-35mm zoom range. I'm really starting to grave for the 50-100mm f/1.8 version too, but it's so expensive and I'd really love it if it would go up too 200mm.
It's not about the gear it's not about the gear it's not about the gear. The best camera is the one that is with you. etc etc