Here are photographs of a waterfall taken at different shutter speeds.
Or, which shutter speed is the best?
The answer depends on how you're using the photograph.
For example, a college promoting its natural surroundings may want to use the high-shutter-speed waterfall photograph.
The photograph would convey the natural beauty of the region, along with energy.
A meditation center, on the other hand, may want to use the more serene slow-shutter-speed photograph.
For the above photograph, the camera was on a tripod.
If it hadn't been on a tripod, the photograph would have shown camera shake because of the slow shutter speed.
Everything in the scene would have shown the movement of the camera, not just the water.
The rocks, water, and everything else, would have been "swirly" and may have had doubled edges.
If you don't have a tripod, set your camera on a stable surface.
If you place your camera on a plastic bag filled with uncooked rice, beans, etc., you can aim your camera more easily.
When using a slow shutter speed, and the camera is on a tripod or on a surface, pressing the shutter release may cause camera shake.
If the moment of exposure isn't critical, you can use your camera's self-timer.
A remote release allows you to trip the shutter exactly when you want, unlike the self-timer.
You can't always use the shutter speed that you want.
You can't use fast shutter speeds with low light.
As you change to faster shutter speeds, and there isn't much light, Lo will appear in the viewfinder.
There's too little light.
You can't use slow shutter speeds in bright lighting.
As you change to slower shutter speeds, and there's a lot of light, Hi will appear in the viewfinder.
There's too much light.
You can use slow shutter speed on a sunny day if you use a three-stop (.9 or 8X) neutral density filter.