Already two of my articles came up under useful articles. It just means that, aside of many expert photographers, there are enough starter users who recognize those basics valuable.
A few words today about shutter speed. Lets just remind that shutter speed is one of the "holly trinity" element when we capture light to our film or sensor. The other two are aperture and ISO sensitivity. I like the metaphor which I read in one book. We can compare those three parameters as catching the sun for bronze tan when you lie down and the beach. Possible hole in the clouds will determine amount of light that will reach your skin. This hole is aperture. Your UV protecting cream factor will determine how sensitive your skin will be to the sun radiation. This is our ISO value. And finally, how long you will stay on the beach under this conditions is representation of shutter speed. Combining all three elements will give you perfect tan.
Now, what is importance of shutter speed. With combination of aperture it directly affects quantity of light that will reach sensor or film. Although, quantity of light could reach the sensor in few different setups. If your correct exposure is f8 with 1/250, then you can catch the same quantity of light with f11 and 1/125. Every f number opens or closes aperture twice. And so every step on shutter speed setting increases or decreases the time of sensor to be exposed (also twice). For example you can walk 10 meters in 10 steps of 1 meter, or in 5 steps of 2 meters, the distance at the end will be the same.
So whats the practical use of this knowledge?
Fast shutter speed captures very short moment of every movement. The movement should be consider relatively, because it can be movement of your object but also movement of your camera. At the sensor level it is a moving image. And movement causes unsharpness or even blur for very obvious reason. Ray of light actually moves through several more pixels on sensor or film. So higher shutter speed (for example 1/400 of second) exposes image for a very short time, and thus lower the chance for anything to move from its place. No need to explain the oposite option.
Before taking any shot we should have in mind what is our goal with this image. If we shooting objects on white, we seek for extreme sharpness so fast shutter speed is the best option to avoid even the smallest movement. Objects on white are special category and shutter speed is not so critical because we can get rid of movements on several ways which I covered in my other article. But if we have descent amount of lighting then the best option is fast shutter speed. The other use of fast shutter speed is to "freeze" something that is obviously moving fast. See the water splash image included. "Freezed" movements are always exciting because image shows details which human eye cannot see clearly. In nature some things are too fast and lazy eye cannot catch all the details.
Shooting from hand is different story. Even if we shoot static scene pressing the shutter will cause a small camera shake. For descent sharpness we must shoot as fast as possible. It will highly depend on lighting conditions since for sharpness we tend to have the smallest possible aperture. For sharp image from hand I would rather compromise aperture to get the best shutter speed. Therefore, cameras have a setting called "shutter priority". You set the shutter speed and let he camera combine the best aperture for this speed.
Now, as every principle has two ways, you may want to have blurry or unsharp image on purpose. There are situations where movement adds to your message on image, depicting some action or faking movement. Example of this is shooting rain drops in counter light. Very fast shooter speed will record dots while very slow will cause image to be covered with lines from top to the bottom. We should find the shutter speed that vill produce short lines caused by raindrops.
So, shutter speed has its creative value. Perfect lighting conditions will give us full range of controlling the capture. But as we know perfect conditions could be done only in properly set studio. In nature, we need to have clear idea what we want to achieve regarding action and movement, evaluate the lighting conditions and then decide about shutter speed at the first place. Simply sadd, when your image concept deals with movement/freezing shutter speed is a priority. If you are skilled you may try one second shutter with zooming your lens at the same time. You may get nice motion blur effect to your image. Sure, always think ahead if this will be stock photo or just art.
Some special effects also may be done with extremely long exposition, like the stars making concentric circles on the sky, or car lights making white and red curves on the street.
The best advice would be: first get known of your camera and its performance features, and then experiment with different setups until you figure out what is best in different circumstances.
Until next time, keep shooting!