You asked
Viltrox af 35mm f 1 7 air vs sony e 35mm f 1 8 oss?
These two are close rivals. Both are 35mm primes for APS-C, both frame like a 52mm lens on full frame, and both autofocus.
The Viltrox AF 35mm f/1.7 Air is the brighter lens, and it fits Sony E, Fujifilm X and Nikon Z, so it's the more flexible buy if you might switch systems. It has no stabilisation.
The Sony E 35mm f/1.8 OSS is stabilised, which helps when you're handholding in dim rooms, but it only fits Sony E.
If you shoot Sony and often work handheld in low light, I'd take the stabilised Sony. Otherwise, the Viltrox is the better all-rounder. Either works well for portraits.
Written by Claude from this site's pages.