Bryan Peterson has written a book titled Understanding Exposure which is a highly recommended read if you’re wanting to venture out of the Auto mode on your digital camera and experiment with it’s manual settings.
In it Bryan illustrates the three main elements that need to be considered when playing around with exposure by calling them ‘the exposure triangle’.
Each of the three aspects of the triangle relate to light and how it enters and interacts with the camera.
The three elements are:
- ISO – the measure of a digital camera sensor’s sensitivity to light
- Aperture – the size of the opening in the lens when a picture is taken
- Shutter Speed – the amount of time that the shutter is open
It is at the intersection of these three elements that an image’s exposure is worked out.
Most importantly – a change in one of the elements will impact the others. This means that you can never really isolate just one of the elements alone but always need to have the others in the back of your mind.