Everything You Need to Know About Aperture

Aperture is one of the most powerful tools you have as a photographer or videographer. It doesn’t just control how much light enters the camera, it also shapes the look and feel of your images. From creating creamy background blur in portraits to keeping an entire landscape sharp, aperture gives you creative control over depth of field, brightness, and even the mood of your shots.

In this guide, we’ll break down everything you need to know about aperture: how it works, why it matters, and how to use it both technically and creatively. Whether you’re just starting out or you’ve been shooting for years, mastering aperture will open up new possibilities for your work.

To learn more about exposure, you should see my exposure triangle guide. If you’re a videographer, I would also recommend checking out the video exposure guide.

TL;DR

• Aperture = lens opening: It controls how much light passes through to the sensor.
• Measured in f-stops (f/1.8, f/2.8, f/8, etc.): Lower numbers mean a wider opening (more light, shallower depth of field). Higher numbers mean a smaller opening (less light, greater depth of field).
• Creative impact: Wide aperture (f/1.4–f/2.8) creates blurred backgrounds; narrow aperture (f/8–f/16) keeps more of the scene sharp.
• Exposure balance: Aperture works with shutter speed and ISO as part of the exposure triangle.
• Bonus factors: Aperture also affects lens sharpness, bokeh quality, and diffraction at very small f-stops.

What Is Aperture?

Aperture refers to the opening inside your lens that controls how much light enters the camera. Think of it like the pupil of an eye, it can widen to let in more light or shrink to let in less.

Aperture size is measured in f-stops (like f/1.8, f/2.8, f/5.6, f/11). A lower f-stop number means a wider opening, while a higher number means a narrower opening. For example:

• f/1.8 = very wide opening, lots of light, shallow depth of field.
• f/11 = narrow opening, less light, more depth of field.

This single setting has a huge influence not just on brightness, but also on the artistic style of your image or video.

The f in f-stop stands for focal length. So f2 in a 50mm lens and a 400mm lens won’t give you the same diameter in actual size.

How Aperture Affects Exposure

Since aperture determines how much light hits the camera sensor, it’s a key part of the exposure triangle (along with shutter speed and ISO).

• A wide aperture (low f-stop) allows in more light. This is helpful in low-light situations or when you want to keep ISO lower for cleaner images.
• A narrow aperture (high f-stop) lets in less light. This is useful in bright conditions or when you want a slower shutter speed for motion effects.

In practical terms, every “stop” of aperture either halves or doubles the amount of light entering the camera. That’s why changing aperture often requires adjusting shutter speed or ISO to keep exposure balanced.

Creative Impact of Aperture in Photography

In still photography, aperture is the main factor that controls depth of field: how much of your image is in focus.

• Wide apertures (f/1.4–f/2.8) create shallow depth of field, where your subject is sharp but the background is beautifully blurred. This is ideal for portraits, product shots, and creative close-ups.
• Narrow apertures (f/8–f/16) increase depth of field, keeping more of the scene sharp from front to back. This is commonly used in landscape, architecture, or street photography where detail throughout the frame is important.

Beyond sharpness, aperture also affects bokeh quality: the look of out-of-focus highlights. Different lenses render bokeh differently, and experimenting with aperture can change how smooth or textured that blur looks.

Creative Impact of Aperture in Video

For video creators, aperture plays a similar role but with added considerations.

• Wide apertures give a cinematic, shallow-focus look, where the subject pops against a blurred background. This is often used in interviews, music videos, or narrative filmmaking to guide the viewer’s attention.
• Narrow apertures are useful when you want to keep action in focus across different depths, like in documentaries, sports, or event coverage.

One key difference in video is that aperture also interacts with shutter angle and ISO. Since you often want to keep shutter speed locked for natural motion blur (like 1/50 for 24fps), aperture becomes the main way to control exposure. That’s why videographers sometimes use ND filters to shoot wide open in bright conditions while keeping motion natural.

Aperture is one of several things that can impact the sharpness of your photos. If you want to learn more, check out this guide on how to take sharp photos every time.

Practical Tips & Pro Advice on Aperture

1. Balancing Sharpness and Depth of Field

Every lens has a “sweet spot” -usually between f/4 and f/8- where it produces the sharpest images. While it’s tempting to always shoot wide open for dreamy bokeh or stopped down for maximum sharpness, knowing your lens’s sweet spot helps when you need reliable clarity.

2. Handling Low-Light Situations

In dark environments, a wide aperture (like f/1.8 or f/2.0) lets in more light and allows you to use lower ISO for cleaner results. If your lens doesn’t open that wide, you’ll need to balance exposure with higher ISO or slower shutter speed.

3. Watch Out for Diffraction

Stopping down too far (f/16, f/22, and beyond) can cause diffraction, where light bends around the edges of the aperture blades and reduces overall sharpness. Use extreme f-stops only when you absolutely need maximum depth of field.

4. Aperture and Lens Personality

Not all lenses render aperture the same way. The number and shape of aperture blades affect bokeh quality, starburst effects from lights, and the overall “look” of your images. Testing your lenses at different apertures is a great way to discover their creative strengths.

5. For Video: Use ND Filters for Creative Flexibility

Because shutter speed is usually locked to match your frame rate, aperture often becomes your main tool for controlling brightness. If you want to shoot wide open on a sunny day, you’ll need an ND filter (Neutral Density) to cut down the light without changing your depth of field or ISO.

6. Combine Aperture With Stabilization

If your lens or camera has image stabilization, you can sometimes get away with using narrower apertures in low light, since stabilization allows for slower shutter speeds without motion blur. If you don’t have stabilization, you’ll need to rely more on aperture and ISO for exposure balance.

Last Words

Aperture is more than just a setting on your camera. It’s a creative tool that defines the depth, mood, and clarity of your photos and videos. By understanding how aperture affects light, sharpness, and focus, you can make intentional choices that elevate your work. Don’t be afraid to experiment. Try shooting the same subject at different f-stops to see how the results change. The more you practice, the more natural it will feel to use aperture as a storytelling tool.

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