This is a technique that smoothes the actions of water, or other moving objects that follow the same or similar paths each time. By using a long exposure to blur the details, it makes all of the movement flow together. In an ocean scene, this can create a fog out of the crashing waves. In a waterfall or river it creates a silky flow of the crashing water. For people moving on a sidewalk or in a moving crowd, it creates a blur of humanity where individuality is lost. You will absolutely need a tripod or other means of stabilizing the camera during the photo. Turn off any vibration reduction or image stabilization your camera might have. To further reduce vibration, you should take the picture using the self-timer if you can. This will let you trigger the photo 2-10 seconds after your hand has pressed the button, which will remove that action as a possible source of camera movement or vibration, and will result in a crisper photo. You will want to set a modest shutter speed – probably from 1/4 sec down to perhaps 10 seconds or longer. The camera will likely decrease your aperture (increase the f-stop) to compensate, but you may need to use a neutral density filter to enable your camera to take such a long picture at all. Experiment with different shutter speeds to determine the best one for your situation.
- Have someone run a hose over a large rock or rocky area. You will need to have your camera on a tripod or otherwise stabilized. Set your camera to the slowest speed that the lighting conditions will allow. This will result in a smoothing of the water splashes. You might try this on an overcast day or perhaps just before sunrise or just after sunset so that you can get an exposure of several seconds.
- Photograph a sprinkler in action. Experiment with different shutter speeds and see how they affect the appearance of the water.
- At a playground or amusement park, photograph a child on a swing, or a merry-go-round or other ride that has a repetitive motion.