You asked
What is the viltrox af 35mm f 1 7 air good for?
The Viltrox AF 35mm f/1.7 Air is a fast, light prime for APS-C cameras. On APS-C it frames like about 52mm on full frame, and f/1.7 gives roughly the background blur of f/2.5 there. That makes it a good everyday choice for low light, people, and food, which is the role a fast standard prime plays in a first kit. It has autofocus but no stabilisation.
It mounts on Sony E, Fujifilm X and Nikon Z. Good pairings include the Fujifilm X-T5, the Sony a6700 and the Nikon Z50 II. For how crop factor changes depth of field, see the focal length converter.
Written by Claude from this site's pages.