So i have decided to move on up from my canon 18-55mm kit lens, but have no idea where to start for my first official lens. I know i really love the sigma fisheye lens but will Force myself to start out with something a little more practical like a telephoto lens/zoom lens for now! Could somebody please give me some advice for a good EF series lens to start out with, also could you advise one that is preferrably good for distance shots. Also what is the difference between canon's L series Lenses and there regular lenses? Also when viewing lenses what does the EF 50MM F/2.5 stand for, does that have to do with aperture, could some one please explain i am new to this, thanks.