You asked
Is the sigma 17mm f 4 dg contemporary good for landscape?
Here is what the site says about that.
From Sigma 17mm f/4 DG Contemporary: Sigma 17mm f/4 DG Contemporary: A prime lens by Sigma for Full frame cameras, 17mm f/4. A tiny metal ultra-wide from the I series; sold as the 17mm f/4 DG DN before 2025. Specs - Maker: Sigma - Focal length: 17mm (prime) - Maximum aperture: f/4 - Made for: Full frame sensors - Mounts: Sony E, L-Mount - Stabilised: no - Autofocus: yes What it frames like - On full frame (Sony E, L-Mount): as ...
From Landscape: Landscape: Landscape photography is slow. The light does the work, the scene doesn't move much, and you can use a tripod. That changes what matters in a camera.
Quoted from this site's pages.