How to make this effect?

[Anders Hattne]

Are you talking about depth of field?
Because if so, that would be best to have filmed like that to begin with.
Otherwise, you’d have to rotoscope the actor, probably track the background, and create a depth matte for it, which you’d later use with A Depth of Field blur, like the Camera Lens Blur that comes with After Effects.

But I guess most of the time you can get away with rotoing the actor and just blurring the background… if that is what you wanted to achieve..>

http://www.ardillamedia.com

[Viola Fionova]

Can you write and show me how to do that step by step with screenshots please?

[Tero Ahlfors]

You’ve asked people to make tutorials for you in multiple threads. Instead of doing that you might try the techniques offered in the other threads. If you don’t understand those then you should probably start with basic tutorials and work your way up. You could also pay a VFX artist to do the shots for you.