Ok so the post regarding lenses for the Nikon D40/40x has made me do a little more homework. Problem is that there is soooo many different lenses out there, how do I know what will work with my D40's auto focus needs? I know AF-S, easy right! I posted a link from Nikon's page below......I'm guessing all of these will work. http://nikon.ca/en/Lens.aspx# What do the 18-55mm numbers mean to me? and what letter must be there to work on Auto focus? I really don't know the difference between lenses and am looking for some clarity. The AF-S DX 55-200mm F4-5.6G ED looks fair priced to me? So why the major price difference? Thanx.