What Is The Exposure Triangle?

One of the most important concepts of photography is something known as the exposure triangle. But don’t worry it is not a mathematical equation and once you learn what it is, it’s actually pretty simple to understand. There are three components in the exposure triangle. These are shutter speed, aperture and ISO. It is called the exposure triangle because of the relationship these three variables have with each other that determine how a photo is taken and what it looks like. In any photograph, these three elements work together. Which means changing one affects the others. To help you understand this and be able to use these components correctly, here is a simple guide on the exposure triangle.

Shutter speed

This is an important aspect for anyone in photography. The shutter speed refers to how fast the aperture in your lens opens and closes. The faster this is the less light enters the camera. Which is why for example when you are photographing in low light conditions, you need a slower shutter speed. Because this opening and closing of the aperture will be slower it will allow more light to enter the camera.

The shutter speed is also important in helping you be able to freeze motion in your photos. So the faster the movement of your subject the faster your shutter speed needs to be.

Why is shutter speed important?

The shutter speed will determine how the image will be captured. For example, as mentioned above when using a slow shutter speed the sensor of the camera is exposed for a significant time. So besides being able to capture darker scenes with the right level of exposure, it also has an effect on moving objects by creating motion blur. This is a creative technique that all photographers use to help show motion in images. Whether it’s waves crashing onto the beach, a dancer or even a light trails from cars, they are all possible through the shutter speed.

Aperture

To understand aperture better, think of it as the pupils in your eyes. If you walk into a dark room, your pupils get bigger to allow more light to enter your eyes. If you then walk out into bright sunshine your pupils become smaller to limit the amount of light entering your eyes. The aperture on your camera works in exactly the same way. The only difference is that you will have to control the aperture on a camera.

Putting this concept into use for photography, it means that if you photographing in low light conditions, you need more light to enter the camera. So a wider aperture is needed in places like covered markets. But if you are photographing outdoors in bright conditions you will need a smaller aperture otherwise your photos will be too bright.

Why is aperture it important?

The aperture not only controls the amount of light that enters your camera but also your depth of field. In other words how much of your image is sharp from the foreground to the background. The wider or bigger your aperture is, the shallower your depth of field (smaller part will be in focus). The smaller the aperture the greater your depth of field will be. For example, in a landscape scene, you will generally want all of the image as sharp as possible. So a small aperture should be used. But for example, when you are taking a portrait of someone, you can use a wider aperture, as they are the only part of the image you need in focus.

ISO

Back in the days of film, ISO would refer to the sensitivity of film to light. In digital photography, all that has happened is that film has been replaced by a digital sensor. ISO controls how sensitive your sensor will be to light. The higher the ISO the more sensitive your sensor will be which means you can take photos in darker conditions. But this comes at a price. The higher your ISO is the more noise you will see in your photo. This will have a negative effect on the overall quality of your photo by making it less sharp.

Why is ISO important?

The reason that ISO is so important is that there are times where you have no other option but raising your ISO. Because otherwise you simply will not be able to capture a photo because of the lack of light. The is especially important in situations where you have to shoot handheld and need to have a fast enough shutter speed to avoid a blurred photo.

They are all linked together

These three elements are all linked together and changing one will affect the others. But it also allows you far more flexibility in being able to choose the settings that you want. For example, as I mentioned earlier, in landscape photography, you will need a greater depth of field which means a smaller aperture. A small aperture will not allow as much light to enter the camera as a wider aperture. So to compensate for this, your shutter speed will need to be slower. A slower shutter speed will mean that even though your aperture is smaller, it will be open for longer allowing more light to enter the camera.

On in another example, let’s say you are photographing someone dancing indoors where there isn’t a lot of light. To be able to capture a sharp photo you will need a fast shutter speed. You can either achieve this by raising your ISO or by selecting a wider aperture. Because if your aperture is bigger, it won’t need to stay open as long as a small aperture. Allowing you to be able to use faster shutter speeds.

The relationships between these three elements in photography form the basis of any photo. If you want to take better photos, you should spend time learning and practising how to use the exposure triangle. Over time it will become second nature to you and you will quickly be able to select and change settings knowing the impact it will have on other elements in the exposure triangle.

Photo credits: Kav Dadfar – All rights reserved. No usage without permission. Dreamstime.