You asked
Is the canon rf 50mm f 1 8 stm good on aps c?
Yes, it's a good choice on APS-C, with one thing to know. On a Canon APS-C body it frames like an 80mm lens on full frame, so it works as a classic tight portrait lens rather than a standard one. f/1.8 gives you roughly the depth of field of f/2.9 there, so backgrounds still blur nicely, just less than on full frame.
If you want something wider for everyday shooting, a 33-35mm f/1.4 to f/1.8 is the better APS-C standard prime, as lenses explains. But if you mostly shoot people, this 50mm is a bargain, and it's the cheapest fast lens on Canon mirrorless. It fits the Canon EOS R7, Canon EOS R10, Canon EOS R50 and Canon EOS R100. For more on framing people, see portraits.
Written by Claude from this site's pages.