I right now have a Rebel T2i with a 18-55 lens and a 75-300mm telephoto zoom lens. I only really do wildlife and some landscapes but its only my second year photographing so my question is should I attempt to a better telephoto lens or is what I have good enough? I'm also going to be doing a 16 day trip through USA this summer so would a better wide angle lens be better if needed? Thanks for the opinions!