A true *blurr* of the background,
with the main subject *sharp* and in focus -
happens when the camera is moved - to follow the Moving Subject. The difference in the fixed bacground and the Movement (or "panning") of the camera causes the background to *blurr*.

If the camera movement exactly matches the speed and direction of the subject (dawg)... the Dawg will appear frozen and sharp on a blurred background.

If the camera movement is slightly slower (or faster), or in a different direction than the dawg is moving; BOTH the subject Dawg AND the background will appear blurred, but to different degrees.

The effect is more pronounced if the subject and camera are moving left or right horizontally; the
effect is much less if the subject is moving toward or away from the camera.

Take LOTS of practice shots - digital "film" is nice and CHEAP!
Don't like the shot?
*Erase* it and shoot another!