The Exposure Triangle – What Is It?

Exposure Triangle – What is it?

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The question has been asked:  I have often seen or heard people referring to the Exposure Triangle, what is it?

In photography, the exposure triangle refers to the three main factors that control the exposure of a photograph: aperture, shutter speed, and ISO. These three factors work together to determine the amount of light that enters the camera and is recorded in the photograph.

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Let’s start with aperture.

Aperture is one of the most confusing settings on a camera because it has two distinct functions. The first function is depth of field, which is a range of distances around the subject of the photograph that are in acceptable sharpness or focus. Depth of field is controlled by f-stops, with a small f-stop number corresponding to a small depth of field and a large f-stop number corresponding to a large depth of field. A small depth of field is often used in portraiture to isolate the subject from the background, while a large depth of field is commonly used in landscape photography to keep the entire image in focus.

The second function of aperture is to control the amount of light that passes through the lens. Again, Aperture is measured in f-stops, and a large aperture is represented by a small f-stop number. For example, f/1.8 or f/2.8 are large apertures because it lets a lot of light into the lens. Conversely, f/16 or f/22 is a small aperture because the iris opening in the lens is small and only allows a small amount of light to pass through. In photography, making the aperture smaller is known as “stopping down,” while making it larger is called “opening up.” It’s important to understand how aperture works and how it affects the exposure and depth of field in a photograph in order to take high-quality images.

Next, we have shutter speed.

The camera’s shutter is a curtain in front of the image sensor that stays closed until the camera is triggered to take a photograph. When the camera is triggered, the shutter opens and exposes the image sensor to the light that has passed through the lens. After the sensor has collected the light, the shutter closes, stopping the light from reaching the sensor. The button that triggers the camera to take a photograph is also called the “shutter button” or “shutter.”

Shutter speed is a setting in photography that refers to the speed at which the camera’s shutter opens and closes during the exposure process. It plays a role in two main functions: stopping motion by using a high shutter speed or creating blur by using a slow shutter speed. Shutter speed also controls the exposure of the photograph by allowing more or less light to reach the image sensor. A high shutter speed allows less light to enter the camera, resulting in a darker image, while a slow shutter speed allows more light to enter the camera, resulting in a brighter image.

Shutter speed is measured in fractions of a second, and most modern cameras can handle shutter speeds ranging from 1/4000th of a second at the fastest to 30 seconds at the slowest.

By understanding how shutter speed works and how it affects the motion, blur, and exposure in a photograph, photographers can take more effective and high-quality images.

Finally, we have ISO.

ISO is a measure of a camera’s sensitivity to light. At higher ISO values, the image may start to show more noise, which is an undesirable grainy texture that can degrade the overall quality of the photograph.

It’s best to use the lowest ISO value when possible, in order to get the highest quality image. This is because lower ISO values result in less noise and a higher dynamic range, which is the range of tones that the camera can capture. However, in certain situations, such as low light conditions, it may be necessary to use a higher ISO in order to properly expose the photograph. In these cases, it’s important to find the right balance between the desired exposure and the acceptable level of noise in the image.

By understanding how ISO works and how it affects the exposure and quality of a photograph, photographers can more effectively control the look and feel of their images.

This makes up the Exposure Triangle

Exposure Triangle

In order to properly expose a photograph, the photographer must balance these three factors, Aperture, Shutter Speed and ISO. The photographer must decide which combination of these factors will result in the desired exposure for the photograph.

It’s worth noting that each of these factors also has its own set of trade-offs. For example, using a larger aperture (smaller f-stop number) will result in a shallower depth of field, but it will also require a faster shutter speed to properly expose the photograph. Similarly, using a higher ISO will increase the camera’s sensitivity to light, but it will also result in increased image noise.

By understanding the exposure triangle and how these three factors work together, photographers can more effectively control the look and feel of their images.

I hope you now have a better understanding of the exposure triangle.