So I bought this R50 a few months ago and I am honestly so frustrated with the kit lens. The RF-S 18-45mm is just... depressing for portraits. My sister is graduating college in three weeks and she wants me to take some nice outdoor shots of her, but everything I take with this kit lens looks flat and the background blur is practically zero. I need something fast.

I have a hard budget of $400 max. I have been researching like crazy and I am stuck between two options. First is the cheap RF 50mm f/1.8. It is super cheap and small, but I keep reading reviews saying the autofocus is kinda loud and it is not super sharp wide open, plus it does not have stabilization. The other option I am looking at is the new Sigma 56mm f/1.4 contemporary since they finally brought it to the RF mount. It is pushing my budget at around $430 but the f/1.4 aperture looks amazing for that creamy bokeh.

Is the Sigma really worth stretching my budget for, or will the cheap 50mm be enough for a beginner doing outdoor graduation portraits?