Shutter Speed

In the exposure section, we have discussed the concept of the Exposure Triangle as a way of thinking about getting out of Auto Mode and exploring the idea of manually adjusting the exposure of your shots.

The three main areas that you can adjust are ISO, Aperture and Shutter speed. We are now going to turn our attention to shutter speed now.

What is Shutter Speed? 

Shutter speed is 'the amount of time that the shutter is open and the image sensor is exposed to light'.  In other words, it is the length of time that your image sensor sees the scene you are attempting to capture.

Shutter speed is measured in seconds ... or in most cases fractions of seconds. The bigger the denominator, the faster the speed (ie 1/1000 is much faster than 1/30).

In most cases you will probably be using shutter speeds of 1/60th of a second or faster. This is because anything slower than this is very difficult to use without getting camera shake. Camera shake is when your camera is moving while the shutter is open and results in blurred photos. Tripods are excellent devices to assist in keeping your camera steady. Typically, slow shutter speed (anything slower than 1/60) requires you to either use a tripod or some type of image stabilization (more and more cameras are coming with this built in).

Shutter speeds available to you on your camera will usually double (approximately) with each setting. As a result you'll usually have the options for the following shutter speeds ... 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc. Because each camera design is unique it may have more or less shutter speed settings, but these examples are very common. This 'doubling' is handy to keep in mind as aperture settings also double the amount of light that is let in ... as a result increasing shutter speed by one stop and decreasing aperture by one stop should give you similar exposure levels.

Some higher end cameras also give you the option for very slow shutter speeds that are not fractions of seconds but are measured in seconds (for example 1 second, 10 seconds, 30 seconds etc). These are used in very low light situations, or when you are applying special effects and/or when you are trying to capture a lot of movement in a shot. Some cameras also give you the option to shoot in 'B' (or 'Bulb') mode. Bulb mode lets you keep the shutter open for as long as you hold it down. This is commonly used to capture a starry night, light writing or an object at night that is bathed in light.

 
 
When considering what shutter speed to use in an image you should always ask yourself whether anything in your scene is moving and how you would like to capture that movement. If there is movement in your scene you have the choice of either freezing the movement (so it looks still) or letting the moving object intentionally blur (giving it a sense of movement).

 

To freeze movement in an image, like in the motor bike race photograph above, you'll want to choose a faster shutter speed. To let the movement blur, like in the stream photograph above, you will want to choose a slower shutter speed. The actual speeds you should choose will vary depending upon the speed of the subject in your shot and how much you want it to be blurred. 

Motion is not always bad, there are times when motion is good. For example when you're taking a photo of a waterfall and want to show how fast the water is flowing, or when you're taking a shot of a racing car and want to give it a feeling of speed, or when you're taking a shot of a starry night and want to show how the stars move over a longer period of time etc. In all of these instances choosing a longer shutter speed will be the way to go. However in all of these cases you need to use a tripod or you will run the risk of ruining the shots by adding camera movement which is an unwanted type of blur.  Sometimes photographers choose to using a panning shot.  This is where the camera follows the fast moving object so it stays clear.  The movement of the camera results in the background blurring. In a panning shot, the photographer must move at the same speed as the subject. Take a look at this shot to see a panning shot in action.


Focal Length and Shutter Speed

Another thing to consider when choosing shutter speed is the focal length of the lens you are using. Longer focal lengths will accentuate the amount of camera shake you have and so you will need to choose a faster shutter speed (unless you have image stabilization in your lens or camera). The 'rule of thumb' to use with focal length in non-image stabilized situations, is to choose a shutter speed with a denominator that is larger than the focal length of the lens. For example if you have a lens that is 50mm, 1/60th is probably sufficient, but if you have a 200mm lens you will probably want to shoot at around 1/250.

 

Bringing it Together 

Remember that thinking about Shutter Speed in isolation from the other two elements of the Exposure Triangle (aperture and ISO) is not really a good idea. As you change shutter speed you will need to change one or both of the other elements to compensate for it. If you use the Tv mode, the camera will automatically adjust the Aperture to try and achieve the perfect exposure.

When you use the Shutter Speed mode it will typically be indicate as Tv (Time Value) of S (Shutter Speed).

This concludes the Shutter Speed section.  Please proceed to  next section, where you will get the chance to Practice Shutter Speed Photography.