You asked
Is the yongnuo yn16mm f 1 8s da dsm good for landscape?
The Yongnuo YN16mm f/1.8S DA DSM is a sensible landscape lens, but only on an APS-C body. On a Sony APS-C camera it frames like a 24mm on full frame, which is a useful wide view for scenery. It's a Sony E mount prime with autofocus, and it isn't stabilised, so you'll want a tripod, which landscape work usually allows.
The catch is resolution. On a full-frame Sony body it only works in APS-C crop mode, which gives you fewer megapixels. Landscape work rewards resolution, so an APS-C body such as the Sony a6600 suits this lens better.
For the full picture on wide lenses, see landscape, and for building a first kit, see your first lenses.
Written by Claude from this site's pages.