I am looking to purchase a wide angle zoon. I have experience with the Tokina 11-16 f2.8 but none with the Canon. I know both are good lenses, but my specific need is for low lighting. Inside my church the lighting is absolutely horrible. Would the extra stop be better than the extra focal distance? 2.8 to 3.5 isnt huge. My other question; Why is the Canon 10-22 not an L lens?