Ever looked back over last years holiday photo’s. They are in focus and you have framed the subject really well. But the photo just looks to dark or maybe its too light. In this post on understanding photography basics we will be looking at exposure and how it plays a role in the making of a great photograph.
What is exposure
Exposure is quite simply the amount of light recorded by the camera’s sensor when you take a photograph.
There are three settings which control the amount of light which is available to the camera:
- Aperture – the hole through which the light has to pass to reach the sensor. The larger the hole the more light which can pass through.
- Shutter speed – this is the amount of time that the shutter stays open allowing light to pass through to the sensor. The longer the shutter speed the more light that can reach the sensor.
- ISO value – this is a number which represents how sensitive the sensor is to light. The higher the number the less light needed to capture the image.
The choices we make when setting the exposure on the camera will have a big impact on how successful you are in capturing the view in front of you in the photograph. We will explore all three settings in more detail in separate posts, but for now think of them as simple values, the higher they are the more exposure and the lower they are the less exposure.
What are the types of exposure
At its simplest there are three types of exposure:
- Correct exposure – meaning that the camera sensor is exposed to just the right amount of light to capture the colour and details of a scene.
- Underexposure – when there is not enough light and the resulting photograph is too dark
- Overexposure – when there is too much light and the resulting photograph will appear too light.
Let us have a look at three photographs showing the difference between under, over and correct exposure.
As you can see in the above photograph, how dark the image is due to being under exposed. If you have an area which is already dark, you lose the details in that area. Notice how the woman’s hair has become a black mass, you cannot see any of the detail in her hair.
In this photograph you can see how bright the image is as a result of being over exposed. The areas which were lighter to start with, the water behind the girl, has blown out into a bright white. You cannot make out any detail behind the woman as a result.
In this final version of the photograph, you can see the importance of having correct exposure. You can see the detail in both the lighter and darker areas of the photo. The ripples can be seen in the water, which couldn’t be seen when the photo was over exposed and the individual strands and colour of her hair can be seen which was a solid black block in the under exposed photograph.
Is under or over exposure always bad?
One way to ensure that your photos are correctly exposed is to leave your camera in automatic mode. The camera will ensure that enough light will make it to the sensor to take the photo, by automatically adjusting the Aperture, Shutter Speed and ISO.
There are times when using the automatic settings will not give you the photography that you are looking for. Time when it may be beneficial for you to either under or over expose your photograph to get the desired look. Below are two examples of when the correct exposure is either under or over exposure.
In the above example you can see that the majority of the photograph has been under exposed. However, this has allowed for the silhouette of the child playing in the water to be captured.
In this second example by allowing the sun to be over exposed, this has allowed for the remainder of the photo to be exposed such that a lot of detail can be seen, particularly the surfers and the pier.
In future posts we will have a look at why we would want to vary the Aperture, Shutter Speed and ISO setting, in particular how these settings will allow us to create wonderful pictures.
Have you had an experience in the past with under or over exposed photographs? Sound off in the comments below and let us know about your experiences.