This is probably a silly question but I have never used a ball head and every shop I've been to that stocks bogen tripods only had the 141RC 3 way head. The Manfrotto 486RC2 ball head ([URL]http://www.manfrotto.com/product/templates/itemalone.php3?itemid=1952[/URL] ) has a "single ratchet locking knob for 360° pan and a double groove for +90°-90° tilt movements." So if you want to do a pano and there is only one knob, once you loosen the ball how can you ensure you just pan without tilting it? Thanks Tony