This question was recently asked in a Google search. Here's what I do:
These aren't water pictures. I have examples somewhere back in my archives but found these first. They're taken using the same methods as water pictures.
To show motion in your water (or fire), set your camera to Tv (shutter priority) and slow your shutter speed all the way down (15 seconds). The SX100 will compensate for the light conditions automatically to keep from over-exposing the picture while choosing the slowest shutter speed possible. Use a tripod. Less light = more motion will appear in the picture (cloudy days, evening, shade, etc.) Water or fire will look almost painted on.
If you want the opposite effect, do the same except choose the fastest shutter speed to freeze the action. More light = sharper "frozen" action.
And that's all there is to it. The camera does the complicated stuff as long as you know how to tell it what you want. The final shutter speed that the camera uses to actually take the picture will most likely not be the speed you told it to use, but will be the most extreme speed that it could use under the conditions.
