Aperture is one of the three pillars of photography, along with shutter speed and ISO, that form the foundation of the Exposure Triangle. If you’re new to photography, understanding aperture is crucial for creating stunning images and achieving the style you envision.
But what exactly is aperture, and how does it influence your photography?
In this guide, I’ll take you through everything you need to know about aperture, from what it is to how it works, its role in depth of field, and practical tips for using it creatively.
Let’s dive in!
Table of Contents
What Is Aperture?
Aperture refers to the opening in your camera’s lens that allows light to enter and reach the camera’s sensor. Think of it like the pupil of an eye - it expands or contracts to control how much light gets through.
Aperture is measured in f-stops, such as f/1.8, f/2.8, f/5.6, or f/16.
These numbers might seem confusing at first, but they represent the ratio of the lens’s focal length to the size of the aperture:
Smaller f-stop numbers (e.g., f/1.8): Wider aperture, more light enters.
Larger f-stop numbers (e.g., f/16): Narrower aperture, less light enters.
Understanding this concept is essential because aperture doesn’t just affect brightness; it also plays a massive role in your photo’s depth of field, sharpness, and artistic impact.
It’s important to note that not all lenses can be used with every aperture setting.
Each lens has its own capabilities, with a minimum and maximum f-number that determines how wide or narrow the aperture can go.
For example, a standard kit lens might have a range of f/3.5 to f/22, while a high-end prime lens might offer a much wider maximum aperture like f/1.4.
To find out what your lens is capable of, check the specifications printed on the lens itself or refer to the manufacturer’s manual. Knowing your lens’s limits will help you make the most of its potential when capturing photos.
Aperture and Depth of Field Diagram
A Quick Note About Aperture Numbers
Understanding aperture can feel tricky at first, but here's an easy way to remember:
SMALL f-numbers = wide aperture (more light, blurry background), and LARGE f-numbers = narrow aperture (less light, more in focus).
Think of it like an open window: a wide-open window lets in lots of light (small number), while a small crack lets in just a little (big number).
It might take a bit of practice and brain memory, but soon it’ll click!
How Does Aperture Affect Depth of Field?
Depth of field (DOF) refers to the portion of your image that appears sharp and in focus.
Aperture is one of the most critical factors influencing DOF.
Wide apertures (e.g., f/1.8, f/2.8):Â These create a shallow depth of field, meaning only a small part of the image is in focus while the background and foreground blur. This is ideal for portraits or isolating your subject.
Narrow apertures (e.g., f/11, f/16):Â These result in a deep depth of field, where most or all of the image appears in focus. This works well for landscapes or architectural photography.
Examples of Aperture in Action
Portrait Photography:
Use a wide aperture such as an aperture between f/1.2 - f/2.8 to create a dreamy, blurred background (bokeh) that makes your subject stand out. How wide your aperture can go will depend on the lens you're using.
Example: A close-up portraiture shot with the background softly blurred.
Portraiture photograph shot using a wide f/1.4 aperture on a prime 35mm lens.
Landscape Photography:
Use a narrow aperture such as an aperture between f/10 - f/16 to ensure the entire scene, from foreground to background, is in sharp focus.
Example: A field of rice crops with every detail in focus.
Landscape photograph shot using a narrow f/14 aperture on a 24-70mm zoom lens.
Aperture and Light
Aperture directly impacts the amount of light hitting your camera’s sensor:
Wider Aperture (e.g., f/2.0):Â Allows more light, great for low-light conditions like indoor photography or night-time shoots.
Narrower Aperture (e.g., f/16):Â Reduces light, useful in bright conditions like sunny outdoor scenes.
Balancing Aperture with Other Settings
When adjusting aperture, you’ll need to balance it with shutter speed and ISO to achieve proper exposure. This is known as balancing the exposure triangle - the aperture makes up one part of the triangle, while shutter speed and ISO make up the other two parts.
Failing to correctly balance the exposure for the shot will result in the shot either being over exposed or underexposed.
For instance:
A wide aperture (such as f/1.2 - f/2.8) might require a faster shutter speed to prevent overexposure.
A narrow aperture (such as f/10 - f/16) might require a higher ISO to compensate for reduced light.
The Exposure Triangle
While many lenses can narrow their aperture to f/20, f/22, or higher, these settings are rarely used by most photographers. Why? At such narrow apertures, light diffraction can reduce image sharpness, particularly on digital sensors. That's not to say they're never used - just rarely by most!
Instead, photographers tend to stick to the sweet spot of the particular lens they're using - which is usually between f/8 and f/16, though it can take some experimenting with each lens - for narrow apertures.
This range tends to best balance sharpness, depth of field, and light control without compromising image quality. Experimenting with these settings and gaining a real understanding of your lens collection will help you find the perfect balance for your shots.
The Artistic Side of Aperture
Mastering aperture is about more than just technical settings; it’s a way to shape the artistic mood of your photos.
Here’s how:
Bokeh:
Wide apertures create beautiful, soft, out-of-focus areas known as bokeh.
Ideal for portraits, macro photography, and artistic shots.
A wide aperture will blur areas of an image that aren't in focus to create what is known as "bokeh", such as the background of this portrait image shot at f/1.4.
Starburst Effects:
Narrow apertures like f/14 can create starburst effects when shooting bright light sources, such as the sun or streetlights.
This long exposure street image was shot with a narrow f/14 aperture which has resulted in a starburst effect being created from the street lights.
Storytelling:
Use aperture to guide the viewer’s attention. A shallow depth of field can isolate your subject, while a deep depth of field can tell a broader story.
A deep depth of field, such as this image shot with an aperture of f/14, ensures that both the background and foreground remain in focus. A shallow depth of field would've resulted in the foreground or background being blurry, depending on where the focus was placed.
Tips for Using Aperture Effectively
Start with Aperture Priority Mode (A or Av):
If you’re a beginner, this mode lets you control the aperture while the camera adjusts the other settings.
Experiment with Lenses:
Prime lenses (fixed focal length) often have wider maximum apertures (e.g., f/1.4 or f/1.8), making them great for experimenting with depth of field.
Practice in Different Scenarios:
Try shooting the same scene with various apertures to understand how it affects the image.
Use a Tripod for Narrow Apertures:
In low-light situations, using a narrow aperture might require a slower shutter speed. A tripod can help prevent camera shake.
Common Aperture Settings and When to Use Them
Aperture is a powerful tool that can transform your photography by controlling light, depth of field, and artistic effects. Whether you’re a beginner or an experienced photographer, mastering aperture opens up endless creative possibilities.
So, grab your camera, switch to Aperture Priority Mode, and start experimenting!
The more you practice, the more confident you’ll become in using aperture to shape your photography style.
FAQs About Aperture
1. What is the best aperture for portraits?
Wide apertures like f/1.8 or f/2.8 are ideal for portraits because they create a shallow depth of field, making your subject stand out against a blurred background.
2. Does aperture affect image sharpness?
Yes, aperture impacts sharpness. Most lenses are sharpest around f/8 to f/11. Extremely wide or narrow apertures can sometimes reduce sharpness due to lens aberrations or diffraction.
3. Can I achieve bokeh with any lens?
Bokeh is easiest to achieve with lenses that offer wide apertures (e.g., f/1.8). However, the focal length and distance between the subject and background also play a role.
4. How does aperture affect video?
In video, aperture controls depth of field and light, just as in photography. Wide apertures are great for cinematic effects, while narrower apertures work for scenes needing more focus.
5. What is the difference between aperture and f-stop?
Aperture refers to the actual opening in the lens, while f-stop is the numerical value representing its size. They’re interconnected but not the same.
6. Why does my camera blur the background?
A blurred background results from using a wide aperture, which creates a shallow depth of field. This technique isolates your subject and draws attention to it.
7. What is the best aperture for landscape photography?
For landscapes, use a narrow aperture like f/8 to f/16Â to ensure most of the scene is in focus.
8. Can aperture affect shutter speed?
Yes! A wide aperture (small f-number) lets in more light, allowing a faster shutter speed. Conversely, a narrow aperture requires a slower shutter speed.
9. What is bokeh, and how does aperture affect it?
Bokeh refers to the blurred background effect in photos. A wide aperture like f/1.8 or f/2.8Â creates smooth, dreamy bokeh.
10. Why are some lenses called "fast lenses"?
"Fast lenses" have wide maximum apertures (like f/1.4 or f/2.8) that allow faster shutter speeds, especially in low light.
11. Does aperture affect the ISO?
Indirectly, yes. A wide aperture lets in more light, so you can use a lower ISO for less noise. A narrow aperture may require raising the ISO.
12. Can I change aperture on my smartphone camera?
Some newer smartphones offer "Pro mode," letting you adjust aperture settings digitally or via simulated depth effects.
13. What is the relationship between aperture and lens quality?
High-quality lenses maintain sharpness even at wide apertures, while lower-quality lenses may produce softness or chromatic aberrations.
14. What does it mean when a lens has a fixed aperture?
A fixed-aperture lens maintains the same maximum aperture throughout its zoom range, making it ideal for consistent exposure.
15. Are prime lenses better for wide apertures?
Yes! Prime lenses often offer wider maximum apertures than zoom lenses, making them great for portraits and low-light photography.
