I am very new in the world of panoramic photography...I own a Canon 5D mark2 and a Canon 8-15 mm fisheye lens...I bought a second hand NN5 just a few days ago and would like to know how to shoot nadir and zenith to be stitched later in the PTGUI pro...I have read somewhere that shooting these can be done handheld -but without loosing the NNP position of the lens - and this looks to be very dificult to me...Hold the camera, remove the big and heavy tripod and at the same time don't loose the no parallax point? How is this done? Any suggestions and comments are highly appreciated...