Zooms For Landscapes
There is a longstanding debate about which is better, zooms or prime lenses. Before you start screaming and running for the hills, relax: I'm not going to open up that can of worms in this tip. What I am going to address is the specific realities of doing landscape work and which can be more useful.
With any lens your primary tool for framing your shot should be your feet, not your lens. Only by changing position can you truly change your perspective. This much can be done with both primes and zooms. The problem is, in landscape work, the best place to stand can sometimes end up being in the middle of a river or over the side of a cliff. You could always change to a different prime lens, but unless you carry a large arsenal of lenses, your choices will be more limited than if you have even two or three good zoom lenses.
Many photography teachers recommend the use of prime lenses when learning about photography based on the premise that one can better understand the perspective that different focal lengths provide. While I agree that the use of focal length as a creative tool relies on learning to see as different lenses do, this can be learned equally well with zoom lenses if one employs a bit of discipline in how they are used. And in real life shooting you may find things a bit more complicated than when you were first learning about lenses.
So long as you don't fall into the trap of stepping out of the car, zooming to frame your composition, and pressing the shutter while still standing in the parking lot, zoom lenses can be a big help for landscape work. Not only can you change positions within the limits of your surroundings just as you can with a prime lens, you can also adjust your framing with a great deal of precision though zooming. Because of their extreme perspective, this can be a huge advantage with ultra-wide angle lenses such as Nikon's 17-35mm AF-S or 12-24mm DX AF-S on a digital body.
What about quality and cost? Zoom lens design is definitely more complicated, no doubt about it. Early zooms were significantly inferior in quality to prime lenses of the day but with today's computer aided design and manufacturing techniques this difference no longer exists. In fact, independent lens tests from respected sources have confirmed that some Nikon professional zooms are even sharper than their non-zooming counterparts. Cost may be a consideration, depending on how many primes you feel you need to substitute for the focal range of any given zoom. Overall though, the difference is not huge and no one ever said photography was cheap.
I'm not saying all this holds true for other types of subject matter, but I'm a definite advocate of zoom lenses for the kind of work I do. To the extent possible, letting your feet determine your perspective and having the zoom range of your lens available to adjust framing gives you the ultimate in flexibility and control your composition. Even when there are rivers and cliff edges near by.