What is the exposure triangle in photography?

The exposure triangle is a fundamental concept in photography that explains the relationship between three crucial settings in your camera: aperture, shutter speed, and ISO. These three parameters work together to control the amount of light that enters your camera (exposure), and also influence certain artistic aspects of your photos.


Aperture refers to the size of the opening in the lens through which light enters the camera. It's measured in f-stops (e.g., f/2.8, f/4, f/5.6). A lower f-stop number means a larger aperture and more light entering the camera, while a higher f-stop number means a smaller aperture and less light.

Apart from light, aperture also influences the depth of field in your photo, which is the extent of the scene that appears sharp. A wide aperture (low f-stop number) gives a shallow depth of field, causing the area behind and in front of your subject to blur. This is ideal for portraits or when you want to isolate your subject from the background. A narrow aperture (high f-stop number), on the other hand, produces a large depth of field, keeping a larger part of the scene in focus, which is ideal for landscape photography.

Shutter Speed

Shutter speed controls the duration that the camera's shutter is open, allowing light to reach the sensor. It's generally expressed in fractions of a second (e.g., 1/60, 1/250, 1/1000). A slower shutter speed means the shutter is open for a longer period, allowing more light to hit the sensor, while a faster shutter speed lets in less light.

Shutter speed also plays a crucial role in capturing motion. A fast shutter speed can freeze motion, making it great for sports or wildlife photography. A slow shutter speed, conversely, can blur motion, providing a sense of movement. This can be used creatively in shooting waterfalls, rivers, or light trails from moving vehicles.


ISO is a measure of the image sensor's sensitivity to light. A lower ISO value (e.g., 100 or 200) indicates less sensitivity and produces darker images, while a higher ISO (e.g., 1600 or 3200) increases sensitivity, resulting in brighter images.

Increasing ISO, however, can result in more digital noise or grain in your images, potentially reducing image quality. Therefore, it's generally recommended to keep ISO as low as possible and only increase it when necessary, such as when shooting in low-light conditions without a tripod or flash.

Balancing the Exposure Triangle

Mastering exposure involves understanding how these three settings interact. Changing one element will invariably require compensating with one or both of the other parameters to achieve a correct exposure. For instance, if you want to use a fast shutter speed to freeze action in low light, you may need to use a larger aperture or increase ISO to let in enough light.

Remember, there's often more than one combination of aperture, shutter speed, and ISO that will provide a correct exposure. The best choice depends on what you're shooting and the creative outcome you're aiming for. For instance, if you're shooting a portrait, you might prioritize a wide aperture for a blurred background and adjust shutter speed and ISO to get a correct exposure.

Understanding the exposure triangle and how to balance these elements gives you the creative control to capture your vision as you see it. This knowledge, combined with practice and experimentation, will help you evolve as a photographer.