This effect is created using a 10 stop neutral density filter (ND filter). My version is commonly refered to as 'The Big Stopper'. It is essentially like placing a welders mask in front of your lens, thereby enormously reducing the light that reaches your camera sensor. This makes it necessary for one to really increase your exposure time and thus allows for any movement to blur in your photograph. I'm new to this and obviously need much practice. See how it blurs ANYTHING that moves. Great for the water but not so much for the vegatation. I am also learning that you must fight noise and artifacts. They too are exaggerated by this technique. It is truely a FUN learning experience, however.