How many times have you seen pictures taken featuring a waterfall with 'ghostly water' similar to the image above? Yes loads, but unconcerned by the many pictures already out there I thought I would add my interpretation for your appraisal and to explain how to get the simple effect.You will need a tripod, neutral density filter (ND) and the ability to set your camera manually. Using a Nikon D200 with a focal length of 27mm a shutter speed of 1/2 a second and F stop 5, this image was created. Pretty easy however: the tricky bit was standing on the top of the waterfall on wet stone trying to maintain my balance. I managed to get away with using a faster shutter speed because the water was moving quickly as I was near the top. Typically ND filters will help you to get the slower shutter speed but of course it depends on how much daylight you have and the speed of the water. In this case there was not much daylight as I was under some large trees on an overcast day. A cable release ( a lead that allows you to fire the camera without touching it) is also helpful but if you do not have one set your camera on self-timer with the mirror up and this should avoid any camera shake.
“A good photograph is knowing where to stand.” - Ansel Adams