What is an aperture iris?

Learn how a camera lens’s aperture iris controls the amount of light that reaches the sensor for perfectly exposed shots.

The iris and aperture are two of the most important parts of a camera lens. Together, they prevent your photos from coming out too dark or light by controlling the amount of light that reaches your camera’s sensor. Here’s what you need to know.

What’s the difference between aperture and iris?

Camera lenses are very precise and complicated pieces of equipment. They’re in charge of magnifying the subject but, more importantly, they control the amount of light let into the sensor — otherwise known as the exposure.

To control exposure, your lens’s iris controls the aperture to restrict the amount of light that reaches the sensor. While the terms are often used interchangeably, there is a difference between the two:

• Iris — Your camera lens works similarly to the human eye. It can open or close depending on the lighting conditions. The iris is the adjustable opening that can restrict the amount of light that enters the camera. It’s the shutters and springs that actually open and close.
• Aperture — The aperture is the hole in the opening of the iris. A wide aperture (low f-stop) lets more light in, while a narrow aperture (high f-stop) restricts it.

How to manage exposure.

Thus, the aperture iris is all about controlling the amount of light that enters the camera.

For low-light environments, open your camera iris for a wide aperture to let in as much light as possible. In bright locations, closing the iris will narrow the aperture and restrict the light that comes in, preventing your photos from being overexposed.

Of course, there’s going to be plenty of trial and error when it comes to adjusting your camera’s aperture iris. If you don’t get the exposure settings quite right, you can always adjust the image exposure later with photo editing software like Adobe Lightroom.

Want more helpful photography tips?

Explore how Lightroom can help you manage exposure and create well-exposed photos every time.