One of my pet peeves is when someone new to photography will ask someone not-so-new to photography: "what's the best landscape lens" and the more experienced photographer will start to recommend all sorts of ultra-wide lenses. ANY LENS can be a landscape lens, from a 15 to a 600!
I took this last night of Mt Adams...hoped to get some meteor shower but the moon was far too bright, it did light up the glaciers very nicely though.
5D Mk III
85mm f/1.2 II
f/2.8, 5s, ISO 1600
I tried a bunch of different f/#, ISO combos: f/1.2, ISO 400; f/2.0 ISO 800, f/2.8 ISO 1600, and f/4.0 ISO 3200...this had the best overall image quality.