I recently purchased a Canon 40D. I haven't received it yet but want to know as much as I can about the lenses before I get them. I'm very new to photography and don't understand "lens speed" or much about lenses at all. I'm going to be shooting mostly concert photography (dim lighting that is random and colored), as well as promotional photos in daylight. The two lenses it came with are an 18-50mm f/3.5-5.6 auto focus, and a 55-200mm 4.5-5.6 auto focus. I'm not sure which would be better for what and if I should get a better lens (I don't want to spend a lot since the Camera was already a huge investment for just beginning). Someone suggested a couple lenses.. http://www.bhphotovideo.com/c/produc...e_EF_35mm.html http://www.bhphotovideo.com/c/produc...0mm_f_1_8.html but if anyone has other suggestions I'd really love to know!