This is my opinion only, but for me there are 2 kinds of panning. One is where you rotate the camera around the axis of its focal plane, like you would have to do if it was attached to a tripod. The other kind of panning is where the axis of rotation is outside the camera, like you wold do if you move the camera at the end of your arm. This is the one that creates interesting distortions, at least for me. I'm sure there are nifty techie words for this, but I don't have them. I'm experimenting now with combining the 2 kinds of panning in one shot, also with rotating the camera in other ways, because I like the distortions. Thank goodness I don't have to pay for processing!