Aperture, shutter speed and ISO: The three musketeers of photography.

These settings will determine how your pictures look in terms of depth, exposure time and light sensitivity. Today, we will be focusing on the last.

Before you learn everything about ISO, consider reading our article on photography 101.

What is ISO in photography?

The acronym stands for International Organization for Standardization, a worldwide organization that develops and promotes international standards in several areas (like technology, working conditions, agriculture, and more).

When it comes to your camera, "ISO" does not refer to the organization itself. Rather, the terminology is used to describe the product that conforms to an ISO standard. In this case, its values refer to how sensitive your camera is to light.

How ISO affects your images?

As I said, this camera setting affects how bright or dark your images will look. As you raise your ISO number, your pictures will turn progressively brighter.

The good news is that higher ISO values allow you to shoot in darker environments. Yet, there is a dilemma: increasing it will also add noise (grain) to your photos, making them less sharp.

The bottom line is you should only increase your ISO when the other methods of improving brightness (adjusting shutter speed and aperture) are not an option.

Common ISO values

Every camera has a different set of ISO values (also referred to as ISO speeds) that you can use. Usually, it is as follows:

  • ISO 100 (low ISO)
  • ISO 200
  • ISO 400
  • ISO 800
  • ISO 1600
  • ISO 3200
  • ISO 6400 (high ISO)

What is Base ISO?

Each camera comes with a value for the lowest ISO setting, called the Base ISO. Some older cameras have a base ISO of 200, but nearly all current digital cameras have a base ISO of 100.

This value is ideal as it gives you the sharpest photo with the least amount of noise. In other words: Try not to mess with it unless extremely necessary.

Low vs high ISO

There is no go-to ISO number: the perfect value will always depend on the situation. Although low ISO is ideal, the conditions may not always allow it, so let us consider when to use each.

When to use low ISO

  • There is already plenty of light.
  • Your camera and subject are entirely still (because you can get the brightness from lowering your shutter speed and increasing your aperture).
  • Landscape photography

Pros: Higher quality image

Cons: Darker results

When to use high ISO

  • With moving subjects (because your shutter speed is already high)
  • Nightime
  • Poor light indoors
  • When using long lenses (again, because you will work with high shutter speed)

Pros: You can get a bright picture without having to manipulate aperture and shutter speed.

Cons: Noise and grain.

How to change ISO on your camera

  • Find your camera's ISO control (check your manual if you can't find it)
  • Start with the base ISO.
  • Scroll through the menu to pick another ISO value.

Example scenarios: Which ISO to use

Street photography in daylight

Daytime generally means using ISO 100 or 200. Since you are shooting moving subjects, which requires fast shutter speed, go for ISO 200.

Indoor portrait photography

For portraits, use a wide aperture. If your indoor scenario is not bright enough, select a higher ISO, like ISO 500 or ISO 600.

Wildlife photography

Wildlife photography calls for high-speed shutter speed, which will damage your lighting. This means you will need a high ISO (around 800).

Nighttime photography

Finally, to shoot at night, you will need at least IS0 1600. Depending on how dark your scenario is, you can use up to ISO 3200.

What's next? Learn everything about photography

As you can see, photography is not as puzzling as it might seem at first. Don't stop now. Learn everything about the history of photography, and all of the basics you need to know right here.


What is ISO in photography?

A camera setting.

What is the function of ISO?

Control your camera's sensitivity to light.

What does ISO stand for?

International Organization for Standardization

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