Aperture is one of the fundamental elements of photography, and it's not hard to see why. Since it profoundly influences both exposure and depth of field, it can completely change the look of a photo.

If you're a beginner, grasping the concept of aperture can be the key to unlocking more creative control over your photographs. We're here to demystify aperture, explain how to make the most of it through your camera settings and illustrate how it can enhance your photos.

The Basics of Aperture

What is Aperture?

A close-up image of a camera lens that’s attached to a Nikon DSLR camera. The user’s hand is turning the aperture ring, which has caused the aperture petals to close into a small circle. 
In the Skillshare class “Aperture: Create Dramatic Blur in Your Portraits,” teacher Tabitha Park shows students what a camera’s aperture looks like when adjusted to a small size. 

Aperture refers to the opening in a camera lens through which light enters the camera. It is measured in f-stops, a scale that denotes the size of the lens opening.

The "f" in f-stop stands for focal length, which is why an f-stop—such as f/2.8 or f/16—indicates the ratio of the lens's focal length to the diameter of the aperture. The f-stop number is inversely related to the size of the aperture, so a lower f-stop number (e.g., f/2.8) means a larger aperture, which allows more light to pass through, while a higher f-stop number (e.g., f/16) indicates a smaller aperture, which allows less light to pass through. In short, a lower f-stop number means more light, while a higher f-stop number means less light.

The aperture, along with the camera's shutter speed and ISO (i.e. sensitivity to light), forms the exposure triangle, a core concept in photography. This triangle illustrates how all three elements affect a photo's exposure, or the amount of light that reaches the camera sensor. If you use a small aperture, for instance, your photo may be too dark unless you increase your camera's ISO and shutter speed.

Wondering just how small or large you can make your aperture? That's dictated by your camera lens' minimum aperture and maximum aperture. If you have a fixed-lens camera, the aperture range it has is the one you're limited to. But if you have an interchangeable lens camera, you can switch to a new aperture range by swapping out one lens for another.

Aperture and Depth of Field

Depth of field refers to the zone of acceptable sharpness in an image, from the nearest to the farthest points in focus. Adjusting the aperture can significantly impact depth of field—here's how:  

  • A wider aperture (i.e., a smaller f-stop number) decreases the depth of field. That means only the foreground will be in sharp focus, while the background of the image will be out of focus. This is also referred to as a shallow depth of field.
  • On the other hand, a smaller aperture (i.e., larger f-stop number) increases the depth of field, which means that more of the scene, from the foreground to the background, will remain in focus.

How Aperture Affects Exposure

Aperture size is an element of the exposure triangle that directly affects the amount of light that reaches the camera's sensor.

  • A large aperture (lower f-stop number) lets in more light, which can be useful in low-light conditions but may also result in overexposed images if faster shutter speeds or lower ISO settings aren't used.
  • Conversely, a smaller aperture (higher f-stop number) lets in less light, which can prevent overexposure in bright conditions but might require slower shutter speeds or higher ISO settings to compensate for the reduced light.

Aperture in Different Photography Scenarios

Aperture in Portrait Photography

A portrait of a woman with glasses and brown hair styled in an updo. She is posed in front of a background of gray stone and green ivy. The woman is in focus, while the background is slightly blurry. 
In the Skillshare class “Aperture: Create Dramatic Blur in Your Portraits,” Tabitha Park demonstrates how the right aperture setting can help a subject stand out.  

In portrait photography, a wide aperture (such as f/1.8 or f/2.8) is frequently used to create a blurry background, which makes the subject stand out. This effect, known as bokeh, adds a professional touch to portraits by isolating the subject from any distracting elements.

Because of this, portrait photographers often prefer lenses with large maximum apertures, such as an 85mm f/1.4 or a 50mm f/1.8. These lenses allow them to create the bokeh effect more easily.

Aperture in Landscape Photography

A landscape photo taken from the inside of a green metal boat floating on an icy lake. The shore is visible in the distance, and is covered with dark trees and white mist. 
In the Skillshare class “Fundamentals of Aperture: Create Images With Depth,” teacher Alan Winslow uses certain aperture settings to add dimension to his landscape photos.  

In general, landscape photography demands a narrow aperture to ensure that both the foreground and background elements are in sharp focus. This large depth of field is essential for capturing the expansive size and intricate detail of natural scenes.

As such, landscape photographers often use wide-angle lenses, such as a 16-35mm, set to a smaller aperture (such as any aperture between f/8 and f/16) to achieve the best results.

Advanced Aperture Settings and Techniques

Aperture Priority Mode

A photo of a woman holding a paper coffee cup out toward the camera. The coffee cup is in focus, while the woman and background are blurry. To the right of the photo is a list of the camera’s settings, including its shutter speed, aperture and ISO. 
In the Skillshare class “Fundamentals of DSLR Photography,” teacher Justin Bridges shows students how they can use aperture priority mode to achieve a softly blurred background.  

Aperture priority mode (typically marked as "A" or "Av" on the mode dial of most DSLR and digital cameras) allows photographers to select the desired aperture while the camera automatically adjusts the shutter speed to maintain proper exposure. This mode is particularly useful for controlling your photos' depth of field without worrying about using the correct shutter speed.

If you don't want to worry about ISO either, you can even pair aperture priority mode with your camera's auto ISO feature, if available.

Alternatively, if you want to learn firsthand how aperture, ISO and shutter speed affect each other in different light conditions, manual mode is the way to go.

Expand Your Photography Skills with Skillshare

Understanding how aperture works and affects photos' appearance is crucial for any aspiring photographer. By experimenting with different aperture settings, you can see for yourself how this single camera setting can dramatically alter the look and feel of your photos, whether they’re street photos, portraits, landscapes or something else entirely.
Ready to become an even better photographer? Skillshare offers a wealth of tutorials and classes on mastering aperture and other photography skills, making it easier than ever to learn the ropes of photography and start creating stunning photos of your own.

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Written By
Carrie Buchholz

Carrie Buchholz

Carrie Buchholz is a freelance writer who lives in Northern Colorado with her husband and dog.

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