Shutter Speed

What is shutter speed?
Every camera has a shutter, the type of shutter will vary for every camera but the function remains the same. The shutter sits in front of the part of the camera where the image is recorded. In film cameras the image is recorded onto the film. For digital cameras the image is recorded by the sensor. 

The shutter can open and close. When the shutter is open, light passes through it onto the film or digital sensor, the presence of light allows a photograph to be made.

Controlling the length of time that your shutter is open for is one of three ways of controlling how much light is let into the camera. See posts on Aperture and ISO for explanations of the other two ways.

As you can imagine, the more light that is let into the camera, the brighter your image will be. The less light, the darker. Although there are other variables that allow you to control how much light can pass into the camera, this post will talk about why and when you would need to adjust your shutter speed, and what effect this has on your photograph. 

How is shutter speed measured?
Shutter speed is measured in seconds or fractions of a second. Each increment is called a ‘stop’. Here’s an example of some shutter speeds,

…2 sec, 1 sec, 1/2, 1/4, 1/8, 1/16, 1/30, 1/60, 1/90, 1/125, 1/180, 1/250 … 

A lot of cameras also feature a ‘bulb’ setting (often labelled 'B'), this is usually found on the Mode dial. When this setting is selected the shutter will remain open for as long as you hold down the shutter button for (the button you press to take the photo). This allows for very long exposures and is something you might choose to use in very low light conditions.  

Which shutter speed should I use?
When capturing movement but wanting to avoid blur e.g. when watching a sports game and wanting to photograph people running across the field. It is necessary to use a very fast shutter speed, such as 1/500 and above, to capture the movement whilst keeping the subject sharp.

When hand holding your camera it is best to only use shutter speeds from 1/60 and above, this is to avoid camera shake.

When wanting to create blur in a photo, e.g. light trails. You will need to use a slow shutter speed, but will want to ensure that the only movement captured is coming from your chosen subject. For example, you want to capture car lights of the traffic at night, so a shutter speed of 3 seconds might be good. But because this is below 1/60 (the minimum shutter speed for hand holding your camera) you will need to have your camera fixed onto a tripod, or resting on a still surface. This way no movement from you holding the camera will interfere with the image (no matter how steady you can hold it, 3 seconds is a long time to stay completely still!).

Examples of shutter speed

Shutter speed of 1/90

Shutter speed of 1 second

In the two photos above you can see clearly the difference that altering the shutter speed can make to your photograph. In the top image the shutter speed was quick, the stream appears sharp and you can see the definition of the waves in the water. Whereas in the second image, the shutter has been left open for longer, allowing time for the movement of the stream to be captured, making the water appear soft and blurry. 

Shutter speed of 1/1000

When your subject is moving very quickly, you need an even faster shutter speed to capture the movement of it. Here you can see the flight of this bird has been frozen by using a shutter speed of 1/1000.


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