To help switch from Auto to Manual, one of the first things you need to understand is the exposure triangle. Aperture, shutter speed and ISO are the three components that make up the exposure triangle and they work together to create the perfect exposure.


So what is exposure and why is it important? Simply put, exposure is how light or dark a photograph is. Too much light and your photograph will seem too bright (overexposed). Too little light and the photograph will appear too dark (underexposed). A perfectly exposed photograph captures the right amount of light without losing details in the shadows or highlights.

The components of the exposure triangle control how much light gets into the camera. Each setting has their own unique function so lets look at each in more detail:


To put things simply, aperture refers to the size of the hole in your camera lens and is measured in F stops. A smaller number refers to a bigger hole and allows more light in. Whilst a larger number refers to a smaller hole and allows less light in.

Aperture also controls depth of field – this is how much of an image is in focus and is the key to creating those blurry background shots. The wider the aperture, the more blurry an image will be.

ISO 100 | F/2.0 | 1/1600

A wide aperture (low F number) creates a shallow depth of field and a narrow aperture (high f-number) gives you a wide depth of field. The above photo was taken at F/2.0 creating a beautiful blurred background and shallow depth of field.

Shutter Speed

The shutter speed is the amount of time the shutter is open and is measured in fractions of a second. This controls the amount of  light coming into the camera. The shutter speed also determines how movement is captured. A fast shutter speed is used when freezing motion (i.e 1/1600) whilst a slow shutter speed (i.e 1/30) is used to create blurred movement.

ISO 250 | F/2.8 | 1/6400


ISO refers to how sensitive your camera is to light. Common values start at 100 and can increase all the way up to 6400, depending on your camera. The higher the number, the brighter the picture. However,  ISO does come with sacrifices. The more you increase the ISO, the more digital noise will be in the image. This means the image will look rather grainy.

The below image used a high ISO of 2000 and when zoomed in you can see the grain it produced. I therefore prefer to keep this low where possible.

exposure - Iso
ISO 2000 | F4.0 | 1/100

It’s a fine balancing act, but once mastered, you will understand the importance of the exposure triangle and how each component impacts one another.

Grab your camera, switch to manual, and start taking photographs whilst adjusting the aperture, shutter speed and ISO. The more you practise the more you will be able to see how the different components work together to create the perfect exposure.