What is ISO Sensitivity in Photography?

Learn the basics for beginners about ISO and how aperture and shutter speed settings interact with each other, by Giulia Candussi

In analog film photography, ISO (or formerly ASA) indicated how sensitive a roll of film was to light. While most modern cameras do not use film anymore, the term stuck around and now refers to the relative sensitivity of a camera’s sensor to light.

Along with shutter speed and aperture, ISO is one of the most fundamental settings to understand when taking digital photographs.

In this video, Giulia Candussi explains what ISO is and how you can use it in your digital photography to achieve the best results possible:

Most DSLR cameras and many phone cameras today will allow you to increase the ISO, and let more light in, or decrease it to capture less.

There is a catch, however. When you increase your camera’s ISO, you will create what is known as “noise”, an effect which will lead to a grainier image.

Thus, every photographer must decide where they draw the line between the amount of light they are able to capture and the amount of grain they are willing to permit in their shot.

If you want to learn more about how to use a digital camera and its settings to start taking high-quality photos, check out Giulia Candussi’s online course Beginner’s Photography: Basic Camera Use and Theory.

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