You asked
Is the laowa 105mm f 2 stf good on aps c?
Here is what the site says about that.
From Laowa 105mm f/2 STF: Laowa 105mm f/2 STF: A prime lens by Laowa for Full frame cameras, 105mm f/2. A smooth-trans-focus portrait lens with an apodisation filter for soft bokeh. Specs - Maker: Laowa - Focal length: 105mm (prime) - Maximum aperture: f/2 - Made for: Full frame sensors - Mounts: Sony E, Canon EF, Nikon F, Pentax K - Stabilised: no - Autofocus: no, manual focus What it frames like - On full frame (Sony E, Canon ...
From Lenses: Your first lenses: 1. A standard zoom, 24-70mm or 24-105mm equivalent. The kit zoom is fine to start. 2. A fast standard prime, a 50mm f/1.8 on full frame or a 33-35mm f/1.4 to f/1.8 on APS-C. Low light, people, food. 3. Then add for what you shoot: a telephoto zoom for wildlife and sport (wildlife and sport), a wide zoom for landscapes (landscape), or an 85mm for portraits (portraits).
Quoted from this site's pages.