Using ScreenPertentage in SceneCapture2D

I am capturing some parts of my game with a SceneCapture2D component and i want to increase the quality of the rendered picture produced by this. I tried to use ScreenPercentage >100, but there is no noticeable effect (i am using a PostProcess Material in case that’s important?) If i use the command line with r.ScreenPercentage = 300 i can clearly see improvements in the game, however when setting the ScreenPercentage in the SceneCapture2D object i don’t see any changes to the rendered picture. Am i missing a setting that i need to change/enable? Or are there other ways to increase the quality rather easy? [The Textures and stuff are good enough and it looks good in the editor, however when rendered it looks less sharp]
Im a beginner in regarding to rendering settings so its quite possible i missed some obvious settings.
I would appreciate any help or tips you can give me.

You want to increase the resolution of your render target texture in the scene capture component settings.

i need the picture to be of a certain resolution and wanted UE to internally calculate with higher resolution and then scale down. If it does not work i will increase the resolution and scale down myself. I just thought there is already an option?