When you think of landscape and cityscape photography, you likely think of wide angle lenses designed to maximize the amount of the scene you can fit in the frame. And while these are the first choice of many photographers, this video makes a great case for why you should also carry along a telephoto lens.
Coming to you from Michael Breitung, this great video shows how a telephoto lens can really expand your repertoire of landscape and cityscape shots while also solving some of the problems of wide angle lenses. I'll be the first to admit that I'm guilty of heading out without a lens above 70mm, and it definitely skews my creative vision in the long run if I forget to bring a telephoto. The nice thing is that for this sort of work, you really don't need the mammoth 70-200mm f/2.8 lenses with image stabilization and large price tags. In fact, Canon makes a wonderful 70-200mm f/4L lens for only $599 (it might just be the cheapest L lens I can think of). It's sharp, light, and exactly what a landscape, cityscape, or travel photographer needs. Most other manufacturers have their own versions as well.