Hey guys. I am planning on shooting a ton of landscape pics in about 12-15 National Parks this summer and was wondering if a Wide Angle lens is a must have for this kind of trip? I have both an 18-55 and a 55-200 lenses that came with my Nikon D40. I have heard a lot about a Sigma 10-20 for landscape shots. If a wide angle lens is a must then what lenses would you guys recommend for a college student on a budget? I don't mind spending a few hundred bucks on a solid piece of equipment that will help me get lots of good shots, but also wouldn't mind having a little money in the bank after the purchase as well! Thanks guys. Forgot to ask if most newer lenses will all automatically focus on a D40. I have heard that the D40 body doesn't do the auto focus, but that it is the lense that has to do the auto focus. Is that correct? thanks.