You asked
Is the sigma 16mm f 1 4 dc dn contemporary good for landscape?
Yes, it can work for landscape, though it isn't really built for it. On an APS-C body it frames like a 24mm on full frame, a natural wide angle for big scenes. Landscape work is slow and usually done on a tripod, so the f/1.4 speed matters much less. You'll mostly stop down to f/8 or f/11, where the lens does its job without showing off. Its speed is more useful for night skies and low light.
Before you buy, read the landscape guide, which explains what matters in a camera for slow, tripod-based shooting. For a basic kit, the lenses page covers the first lenses worth owning.
Written by Claude from this site's pages.