Are you wanting to know how to make the background blurry while keeping the figure "crisp"? If so that is done using filters in post work.  Gausian or zoom blurs, softening etc.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi