Photography basics: ISO speed.

Learn more about the basics of ISO, the various speeds, and how those speeds affect your photos.

If you’re new to photography, capturing photos on the camera’s automatic settings will result in clear, balanced photos almost every time. But understanding the various camera settings and how they affect your photos helps open up the world of photography and gives your creativity free reign.

One of those important settings to know and understand is ISO.

What is ISO?

ISO is your camera’s sensitivity to light as it pertains to either film or a digital sensor. In the most basic terms, it will play a role in brightening or darkening a photo. Together with aperture and shutter speed, ISO makes up the third fundamental pillar of photography.

You’ll see the different ISO settings written as numbers (also known as speeds). These numbers were set by the International Organization for Standardization (that’s where the name came from).

Common ISO speeds and what they mean.

While every camera offers a different range of ISO values, there are common sets you’ll come across no matter the model. It’s common to refer to the lowest ISO setting as your “base ISO.”

Here’s a typical standard set, ranging from low to high ISO:

You’ll notice that these speeds double as the numbers increase, which correlates directly with brightness levels. This means that an ISO of 800 will add twice as much brightness to your photo as an ISO of 400.

How does ISO affect my photo?

The lower your ISO, the less amount of light is let in, but the higher your photo quality. Conversely, when you bump up your ISO, you’ll get more light. Increasing the light too much, however, can show a lot of grain — also known as “noise.”

Together with managing aperture and shutter speed, setting the ISO speed is always part of a delicate balancing act to get enough light without sacrificing quality.

Discover photo tips and techniques as you begin to play around with your camera’s manual settings.

When you’re ready to edit your photos, explore everything you can do with Adobe Lightroom.