Unit Four : The Exposure Triangle
The Exposure Triangle
The exposure triangle is a term you will hear thrown around photography circles - and for good reason. Understanding the exposure triangle is the fundamental basis for getting complete control over your photos. So what is it?
The exposure triangle is a fundamental concept in photography that describes the relationship between three crucial elements: aperture, shutter speed, and ISO. These three components work together to control the exposure, or the amount of light that reaches the camera sensor, ultimately influencing the brightness and quality of an image.
A visual representation of the Exposure Triangle. Download a high-resolution version here.The Settings
The exposure of your image depends on the three settings that make up the exposure triangle. We’ll go over each in detail in individual lessons, but let’s have an introductory look at each element.
Shutter Speed. The camera's shutter is like a quick-opening and closing curtain inside the camera that controls how long light is allowed to reach the camera sensor. Shutter speed is how long it takes for that curtain to pass over the sensor or film. The quicker the speed, the less light hits the sensor/film, and vice versa. The amount of time that the shutter is open also affects how much motion is recorded. More on that later in this lesson.
Aperture. As we saw in our gear unit, the aperture is a hole in your lens through which light enters before hitting the sensor/film. The wider the hole, the more light hits the sensor/film. Your aperture not only has an effect on how much light is present in the image but is also an important aspect in determining depth of field, which you will remember refers to the range of distances within a photograph or image where objects appear acceptably sharp and in focus. We’ll see this in practice in the next lesson.
ISO. ISO represents the amount of amplification that occurs to the signal that the sensor receives. A higher ISO represents more amplification, and a lower ISO represents less amplification of this signal, with the greater the amplification resulting in a brighter image of the same scene. Higher ISOs also introduce grain or digital noise to the image - how much depends on individual cameras. In film, ISO is a characteristic of the film itself and on digital cameras, you have the ability to adjust the ISO. We’ll learn more about ISO in lesson 9.
Remember this is just a quick overview to give you an idea of what we will be covering in the coming weeks. What is important to know at the moment is that each setting has an effect on others, and controlling the exposure means finding a balance between the three. It's like a dance between the lens aperture, the speed of the shutter, and the sensitivity of the camera sensor to capture the perfect shot - and we’re going to learn the steps.