So many replies to a question of this sort, ie "Landscape" issues seem to imagine that one is standing on the edge of a geometric plane with the freedom to place the camera anywhere along this "edge" and the further freedom to advance or retreat from the "edge" in order to perfectly frame the desired composition with the perfect prime. Now that situation does exist, but I more often than not find myself at the head of a bay, the apex of a point, the edge of a precipice, near the foot of a cliff, in the proximity of, but not able to get closer to, a desired foreground element, and on and on ad infinitum. Suffice to say that my choice is usually for a zoom lens that allows me to frame the composition exactly as I choose without having to physically move the camera into the ideal position for a prime lens however superior its resolution or contrast. Do I have primes in my twenty five pound pack? Sure. Do I plan for the situation that will allow me to use them? Of course. But when I want to be able to walk through the landscape relatively unencumbered yet ready to respond to changing light and perspective I am ready to accept whatever IQ restrictions are placed on me by a 16-35 and a 28-300. I would rather have the image I envision than wish I could place my self or my tripod in the middle of thin air or a body of water so that the prime lens was situated just so.