Within the camera you have multiple components. One of the most important of these is the shutter. The shutter opens when the picture is being taken and shuts to cut off the light. In film photography the shutter was key as it would allow the film to be exposed to light for a set amount of time. This is the same in digital cameras but they have a sensor rather than film. The length of time the shutter is open for is determined by a setting called the shutter speed.
This is often found in fractions of seconds and whole numbers. The fastest shutter speed available on my Nikon D3200 is 1/4000th second. This would expose the sensor to light for a very sort amount of time, useful on a very sunny, bright day. The slowest shutter speed is 30 seconds, leaving lots of light to get to the sensor. This would be used at night when it is very dark. There is also one more option available if you scroll all the way to the 30 second end and go on a bit. It is called ‘bulb mode.’ Bulb mode allows you to choose any length of time for the shutter to be open for. It is activated by the first click of the shutter button and turned off by a second. For this setting I use a remote trigger to prevent camera shake. Click here to see the remote I use.
Shutter speed is also key when you are trying to capture movement. Using shutter speeds like 1/2500th second on a waterfall will freeze the action. If a slow shutter speed of 1/5th second is used on a waterfall it will begin to blur out the water in long streaks as it falls. This can be nice to the eye. People often used 5 second or slower shutter speeds on rivers to give the water a glassy, smoothed out effect. This isn’t always possible during the day though because too much light gets to the sensor, leaving an under-exposed image. This can be prevented by using an ND-filter. (One item on my Christmas list!) The ND-filter prevents so much light entering the lens which allows those slower shutter speeds to be used in broad daylight. These can be brought in multiple ‘stops’. A 10 stop will lower the amount of light by 10 stops, perfect for a long shutter speed. With a 2 stop you can step your shutter speed down by 2 stops so a shutter speed of 1/500th second will be able to become a 1/125th second shutter.
Slow shutter speeds can also be used in light painting. Click here to see an example of light painting. The faster shutter speeds are useful for freezing movement so I used them here, here, here and here.
Above is an example of a 1/50th second shutter speed, fast enough to capture the ripples in the water
Above is taken on the same day in exactly the same place as the other, however this was taken with a 3 second shutter speed. This long exposure allowed the water to be smoothed out and given a glassy look.