How To Blur Distance With Depth Of Field?

Hi, I played around with this for quite a while, but whatever I do I can't get a setting that seems right. I would like to blur the background/distance of my game. I don't need a dynamic focus, just a static "blur anything farer away then x gradually". Whenever I play around with the Depth Of Field from the Post Processing it results in either blurring everthing, nothing, or fore and background. How do I fix this issue, do I need a seperate shader maybe? Thanks in advance!