At the outset this might seem as unfathomable as the Bermuda Triangle…and to some it always will be but let me try and break it down so that it might make a little sense.
We’ve already mentioned that aperture, shutter speed and ISO are all linked. They are all methods of changing the amount of light that the camera sensor records to form the image. Changing one often means that you have to adjust one or both of the others – they are inextricably linked and are often noted together in a triangle.
Consider the following image and think about the three elements linked together to change to quality of the final image required.
Getting the right exposure – or the desired exposure – for an image is at times an art – but it is taking all these three elements and blending them together, adjusting one to offset one of the others that is the key to a great looking image.
Why bother though when you can make the camera do all the decision making for you? Well, if you want to make your images pop and raise their quality significantly you should understand all this and know how to change these together. The difference in quality will astound you and you will be well on your way to more professional looking images.
Your camera can only do so much with the data it reads about the scene and sometimes it just gets it wrong. Some elements (such as a bright source of light) can confuse it and as a result it makes the wrong decision on where to set exposure within the triangle.
Let’s take a moment to consider an example. Imagine you have the perfect exposure of an image and it really pops but the subject of the image is a fast moving car and it looks a little blurry. You can fix this by increasing the shutter speed to capture the image more quickly. But, without adjusting ISO and / or aperture the exposure of the image has now changed (less light from the faster shutter speed) and it will be underexposed. You can therefore increase the shutter speed to capture the fast moving object more static (without a motion blur) and then change the aperture to let more light in to increase the exposure at the same time. Achieve that balance again for the perfectly exposed image that captures the object in a perfect moment of time. The triangle works!
The exposure triangle is a clever little thing and is at the heart of all great images. Manual mode makes all the decisions for you and gets the correct exposure for any given image but I’ve already mentioned that changing the settings of the triangle elements can really make your images pop.
What’s the difference?
Well, the three elements of the exposure triangle have some other impacts on the final recorded image:
- Aperture also controls something called the depth of field. Have you ever seen an amazing portrait image of someone where the background is all blurry so that your eye is drawn to the person (subject) in the image? Aperture controls how much of the image is in focus…from the foreground, through to the subject and beyond to the background.
- Shutter speed helps us to control how we capture motion in an image. A fast shutter speed and even something moving at speed will be captured still (more or less if you have a fast enough shutter speed) whereas if you use a longer shutter speed objects can be shown to have movement. Combine some still and moving elements into a single image and you’ve cracked it!
- ISO can effect the quality of the final image. High ISO can introduce some grain and make your image look a little aged or worn.
So you can see that controlling these three elements can have a massive impact on the look and quality of the final image. Control these and you control your camera. Well, not really. There’s still a lot more to go but you get the idea.