The 3 Pillars of the Exposure Triangle

The famous exposure triangle is a fundamental tool to achieve the correct exposure in our photographs.

By combining in a balanced manner the diaphragm, the shutter time and the ISO sensitivity, we achieve a perfect image from a technical point of view. Although it has been taught for decades, it is worth revisiting in the context of modern digital photography.

Table of contents

What is the exposure triangle?

The exposure triangle is composed of three elements: diaphragm, shutter speed, shutter time and ISO sensitivity.

These three pillars work together to control the amount of light reaching the camera sensor and determine how an image is captured.

Importance of the exposure triangle

Understanding and mastering the exposure triangle is crucial for any photographer, as it allows you to have the ability to full control over the resulting image. Knowing how these three elements interact helps us to make informed and creative decisions when taking a photo.

The 3 Pillars of Exposure

The three components of the exposure triangle are interconnected. Changing one of them means adjusting at least one of the other two to maintain a balanced exposure.

For example, if you increase the aperture to let in more light, you may need to shorten the shutter time or reduce the ISO sensitivity.

Adjusting the exposure triangle involves finding the right balance between the three elements to achieve the desired exposure. This requires practice and an understanding of how each adjustment affects the final image.

he Diaphragm

The aperture is an opening in the lens that can be adjusted to control the amount of light entering the camera.

It is measured in f-numbers, and a lower f-number indicates a larger aperture.

How it affects depth of field

The diaphragm not only controls the amount of light, but also the depth of field, which is the amount of the image in focus.

A small f-number (large aperture) produces a shallower depth of field, ideal for portraits. A large f-number (small aperture) produces a greater depth of field, suitable for landscapes.

f numbers and their meaning

The f numbers can be confusing at first, as they seem to go backwards. A higher f-number means a smaller aperture, and vice versa.

This is because the f-number is the result of dividing the focal length of the lens by the diaphragm diameter.

Shutter Speed

The shutter time is the time during which the camera shutter is open and allows light to reach the sensor.

It is measured in fractions of a second or whole seconds.

How it influences the movement of the image

The shutter time determines how motion is captured in an image.

Fast shutter times freeze motion, while longer shutter times can produce a blurred effect.

Common shutter times

Common shutter times vary from fractions of a second, the camera can be used to capture fast motion, such as 1/500s for freezing fast motion, up to several seconds for capturing low-light scenes or creating motion effects.

ISO sensitivity

The ISO sensitivity is a measure of the camera sensor's sensitivity to light.

Higher ISO values mean that the sensor is more sensitive, allowing pictures to be taken in low light conditions.

How noise affects the image

Setting the ISO to high values can introduce noise in the image, an unwanted effect that appears as grain or dots in the photo.

It is important to find a balance between sensitivity and image quality.

Recommended ISO settings for different conditions

For bright light conditions, low ISO values are recommended (100-200).

In low light situations, higher ISO values (800-3200) can be used, taking into account the possible increase in noise.

Application of the Exposure Triangle in Digital Photography

In the digital age, the exposure triangle is still relevant, but with some adaptations.

Modern digital cameras offer advanced tools such as histogram and real-time preview, which make it easier to adjust exposure.

Digital tools for adjusting exposure

Digital cameras allow precise exposure settings through intuitive menus and settings.

In addition, the editing software allows you to post-processing adjustments to refine the exhibition.

Practical examples of adjustments in different situations

In portrait photography, we might use a wide aperture (small f-number) for a blurred background, a fast shutter time to avoid subject movement, and a low ISO to minimise noise.

In landscape photography, a closed aperture (high f-number) for greater depth of field, a longer shutter time to capture more light, and a low or medium ISO to maintain image quality.