4. Exposure – Shutter Speed

Pictures by Pam Redgrave and Neil Douthwaite

The shutter speed controls how long your camera is taking a photo for. A fast shutter speed means that the shutter is open for a very short space of time. This means that the camera has only a short time to collect light. A slow shutter speed gives your camera more time to take in the light that makes up a picture as the shutter is open for longer.

SLR cameras still have a mechanical shutter which is why they make a distinct ‘click’ when the picture is taken. In simpler cameras the shutter speed is simply the time that the digital sensor is collecting information.

Shutter speed is measured in fractions of a second. So a speed of 1/100 means the shutter is open for 100th of a second. On many camera the speed can range from 1/4000 to 30 seconds, or even using the Bulb setting for as long as you hold the shutter button.

As a general rule a shutter speed slower than 1/60 may require a tripod to hold the camera steady and prevent blurring but this will depend on the lens you are using and how far you are zoomed into the subject.

For most subjects you will want to select an exposure that has the right balance. However, there is no absolute answer. You will also notice that some photographers choose to deliberately under expose or over expose their pictures as part of their artistic expression. In the pictures below Pam has taken a photo of a flower using three different shutter speeds.

Over-Exposed
1/400
003
1/800
Under-Exposed
1/1600

 

 

 

 

 

  • You can see that in the photo taken at 1/400 the flower looks wasked out, often called burnt-out. The camera has been able to take in too much light and as a result some detail has been lost.
  • At 1/1600 the shutter has been open for only a very short space of time. As a result the photo looks a little dull and dark. In extreme examples all detail can be lost and the photo is blackened.
  • At 1/800 we have a better compromise with good detail in the flower and a good reproduction of the colours.

If you want to get a good exposure though one way is to find the ‘bracketing’ function on your camera. In this setting three photographs will be taken at different exposures. This reduces the risk of not getting the exposure right first time. However for small adjustments to the exposure of a photograph even the simplest image editing software can compensate for small adjustments.

One other thing to remember is the effect the shutter speed can have on the appearance of the photo. To take a perfectly crisp photo the quicker the shutter speed the better, without it being too dark. However, you can create a blurred effect by using a slower speed. As the camera or subject moves the length of time that the shutter is open will create a blur which is sometimes desirable. In the Neil’s photo below the shutter speed is 1/320. Because a Formula One car travels a long way in 1/320th of a second and by following the car in the view finder, the wheels, sparks and background blur to create a sense of speed an movement that a fast shutter, with no blurring would not have created.

DSC09447c
1/320
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