Addition to the previous post:

I created a new scene and rendered it, everything was fine.
I switched DoF on, took a render and DoF worked as expected.
I switched DoF off and took a render with face, dolly, aux, hand and posing camera...DoF was always active.
I created a new camera, rendered the shot and...still DoF is on.
The moment you switch DoF on, the scene can't be rendered without DoF anymore.
I also tryed to get rid of it by hitting the undo button to the point the scene was empty.
It doesn't work.