I was considering the lens once, but backed off when they talked about all the aberrations it had. Where I needed it, there was always gonna be a Window with a ton of light coming through. I've been making due with the tamron 17-50 and stitching shots together in post. As for upgrading to the 7d, I'd love to sell you mine, but I don't think you'll see enough of a difference in the camera you have for what you're doing. Granted you can't take the T3i, throw it in a tub of water, freeze it, use an gun to blow the chunks of ice off, set it on fire, and still be able to take pics with it.