thanks for the comments everyone. I have a 350D and had a cheap sigma 70-300 lens. I snuck it in by building a little compartment in the bottom of my backpack with some Velcro and black felt. I just put some stuff on the top, plus they didn't check it very hardcore. I only used it one night, which ended up good because the next night they guy checked my bag really well and would have easily found my camera. I felt a little distracted with my camera during the concert but am definitely happy i took it in.