Aperture for Beginners: A Complete Guide to Depth of Field and Bokeh in Photography
Aperture is one of the most important settings in photography because it directly affects how bright your image is, how much of your scene is in focus, and how your background looks. If you’ve ever wondered how photographers get soft, blurry backgrounds or sharp images from front to back, aperture is the key. In this beginner-friendly guide, you’ll learn exactly what aperture is, how it works inside your lens, how it affects exposure and depth of field, and how you can use it creatively to shape bokeh and visual style.
Table of Contents
What Is Aperture in Photography?
Aperture is the opening inside your camera lens that allows light to pass through to the sensor. You can think of it like the pupil in your eye: it opens wider in dark conditions and becomes smaller in bright light. When you change your aperture, you control two important things at once:
How much light enters the camera
How much of your image is in focus (depth of field)
Along with shutter speed and ISO, which you’ve already learned about, aperture is one of the three main pillars of the exposure triangle, a concept we’ll dive into later 🤓
How Aperture Works Inside Your Lens
Inside every camera lens is a set of thin metal blades that form a circular opening. These blades move when you adjust your aperture setting. When you choose a wide aperture, the blades open up to create a large hole. When you choose a narrow aperture, the blades close down, making the opening smaller. This opening determines how much light reaches the sensor during an exposure. The shape and number of these blades also influence how out-of-focus areas look in your photos, which affects bokeh quality. Rounded aperture blades tend to give rounder more visually pleasing bokeh-balls. Also lenses with more aperture blades tent to give more pleasing bokeh-balls and softer defocused background which leads to higher prices. Why does the size of the opening in the aperture affect how blurry the background is? Well hold onto that that thought we will get to that but first let’s understand the basics.
Understanding f-Stop Values
Aperture is measured in f-numbers, also called f-stops. Common aperture values include:
f/1.4
f/1.8
f/2
f/2.8
f/4
f/5.6
f/8
f/11
f/16
f/22
The confusing part for beginners is that smaller numbers mean larger openings. For example:
f/1.8 = very wide opening
f/8 = medium opening
f/16 = very small opening
Each full stop lets in half or double the amount of light just like each ISO stop halved or doubled the light sensitivity. Your lens has a maximum aperture (widest it can open) and a minimum aperture (smallest it can close).
Also worth mentioning is that the smaller the F-number the more light a lens can let in through the lens and onto the sensor. So an f/1.2 lens will let in a lot more light than an f/2.8 lens which let’s in a lot more light than an f/4 lens. But what does that mean in the real world? Two things:
A lens with a lower F-number will be better at shooting in low light because it can get more light to the sensor.
For portrait photographers and videographers who like a shallow depth of field and a soft creamy bokeh for subject separation the smaller the f-number the softer the bokeh.
💡💦 One way to look at aperture is thinking of it like a hose. Imagine you’re watering your lawn with a hose. When you close down the hole in the nozzle you get less water going through but it shoots out farther. When you open up the nozzle in the hose more water is able to go through and the water spreads wider but doesn’t go as far. Now think of that water as light. When the aperture of the lens is closed down less light gets into the sensor and your depth of field stretched out farther. But when you’re aperture is fully open you let more light into the sensor but the depth of field doesn’t go very far.
Wide vs Narrow Aperture: Pros and Cons
Advantages of Wide Aperture (f/1.4–f/2.8)
Lets in lots of light
Works well in low light
Creates blurry backgrounds
Separates subject from background
Produces strong bokeh
Wide apertures are ideal for:
Portrait photography
Low-light shooting
Street photography at night
Artistic photography
Disadvantages of Wide Aperture
Very shallow depth of field
Harder to manually focus
Less of the scene is sharp
Can show lens imperfections
Advantages of Narrow Aperture (f/8–f/22)
Greater depth of field
More of the scene in focus
Better for landscapes
Improved edge-to-edge sharpness
Narrow apertures are ideal for:
Landscape photography
Architecture
Group photos
Product photography
Disadvantages of Narrow Aperture
Lets in less light
Requires slower shutter speeds
May require higher ISO
Can introduce diffraction softness
Aperture and Depth of Field Explained
Depth of field refers to how much of your image appears sharp from front to back. Aperture is the main factor that controls depth of field. You may have seen this graphic on social media a million times already but here it as again with an explanation.
aperture cheat sheet
Depth of field example - which is better? f/1.4 has a shallow depth of field with lots of subject separation. (as in separated from the background) The second image at f/8 has a wider depth of field meaning more of the background is in focus.
What these images are essentially showing is “depth of field”. Depth of field is how much of your photo appears sharp and in focus from front to back. If only your subject is sharp and the background is blurry, you have a shallow depth of field. If most of the scene, from foreground to background, is sharp, you have a deep depth of field. Depth of field is mainly controlled by three things:
Aperture: Wider openings (like f/1.4) create a shallower depth of field. Smaller openings (like f/8) keep more in focus and have a deeper depth of field.
Distance to your subject: The closer you are to your subject, the blurrier the background becomes. You can use this trick to enhance background blur with any lens.
Lens focal length: Longer lenses naturally create more background blur than wide lenses. An ideal portrait lens for really soft background would be a 135mm.
Sensor size: The smaller the sensor the more natural depth of field you can get. For example if you have an APS-C sensor with an f/1.4 lens and a medium format sensor with a f/1.4 lens the medium format image will have a softer background. That’s why tiny sensors like the one in your phone need special processing to create that (portrait mode) blurred background look.
When Should You Blur the Background?
From a creative perspective, it’s important to ask yourself when to use a shallow depth of field and when a deeper depth of field makes more sense. I created the example images above to illustrate this idea. The image on the left uses a shallow depth of field, creating beautiful subject separation, but it also sacrifices much of the scenery in the background. The image on the right is more immersive. Neither approach is right or wrong, it simply depends on the story you want to tell.
As photographers and videographers, the goal is to be thoughtful with our choices and create images with intention. Photographers use depth of field creatively to guide the viewer’s eye, blurring distractions or keeping everything clear, depending on the story they want to tell. 📸 If you’re shooting a portrait of someone as a headshot you might want a shallow depth of field burring the background and keeping the focus on the subject. On the other hand if the background is part of the story then you want a deeper depth of field to enrich the story of the photo.
Below is an image I shot for a swimwear campaign. The swimwear had a lot of animal print so I wanted a background that was a little more wild instead of the typical beach shots. I put the model in some shrubs with a tree behind her. I knew that I wanted the tree in the background to be defocused in order to create subject separation or the model would get lost in the busyness of leaf shapes. So I used a 200mm lens at f2.8 to create bokeh behind the model.
Below is another image from that campaign. In this situation I was trying to create a mood shot to set the vibe for the image set. I wanted to convey the feeling of a wild animal in it’s natural habitat. In the previous image we used a scrim to soften the sunlight in this shot the model was exposed to direct sunlight. I posed the model in order to create some shade across her face to add to the mystery of the image. If you understand composition you’ll also notice I used a strange composition to bring out an awkward wild feel. And finally to the aperture, I used a wider aperture to create a wider depth of field to keep more of the grass in focus adding the mood of the image. If I had used a shallow depth of field and isolated the model it would have no longer been a mood-setting environmental portrait. Images like this in a pictroial spread are often called establishing shots. They set the vibe for the rest of the images.
Here is an example photo shot with my favorite portrait lens the RF 85mm f/1.2 L. This image is shot to create a shallow depth of field and blur out the distracting background thus allowing the viewer’s attention to focus on the model’s face. I’m also using leading lines to direct the viewer’s attention towards the model. We’ll talk more about that in the composition blog series.
Wide Aperture = Shallow Depth of Field
Small area in focus or shallow depth
Blurred foreground and background
Subject stands out
Narrow Aperture = Deep Depth of Field
Large area in focus
Foreground and background are sharp
More detail throughout the scene
Depth of field is also affected by:
Focal length
Distance to subject
Sensor size
But aperture has the strongest influence.
🎯 Some Pro Tips:
For product photography an APS-C sensor can be better because it naturally has a deeper depth of field.
If you’r shooting group shots at wedding for example a good general rule is to set you aperture to the number of people you have in the group to get all the faces in focus. More people generally need more depth of field. I learned this lesson the hard way shooting a group of people at f2.8. 😭 So two people = f/2.8, five people = f/5.6, eight people needs f/8 and so on.
Don’t go crazy with the Bokeh. It’s nice to have a shallow depth of field but it’s also important to create with intention and story.
Lenses that have an aperture that can open up bigger than f/2.8 are called “fast lenses”
If you plan on shooting natural light or at night your best bet is a full frame sensor and a fast lens.
Cheat sheet - aperture settings for shooting group shots
How Aperture Shapes Bokeh
Bokeh refers to the appearance of out-of-focus areas in a photo, especially highlights in the background. Aperture plays a major role in determining how bokeh looks. Aperture Size and Bokeh
Wider apertures create larger, softer blur circles (Bokeh Balls), making backgrounds look smooth and creamy. Narrow apertures create smaller, more defined blur shapes. Here is a short video that shows off some bokeh to give you a better understanding: The King of Vintage Bokeh - Helios-40 85mm f1.5
Here is an image showing two shots one with a narrow aperture (on the left) and one with a wide aperture (on the right). It shows the difference in background blur you can get with one lens. The round balls of light on the right are called bokeh-balls. They are round in the middle. Towards the edges of the frame the bokeh-balls become elongated and are called Cat Eye Bokeh.
Some lenses have optical quirks that affect the look of boke-balls. In this case what you’re looking at is an optical imperfection that creates Soap-Bubble Bokeh. Boheh-balls with a distinctive highlight around them.
Aperture Blade Shape
The number and shape of aperture blades affect bokeh quality.
More rounded blades = smoother bokeh
Fewer straight blades = polygon-shaped highlights
High-quality portrait lenses often use rounded blades for this reason.
Here is an image shot with a lens that has 8 (non-curved) aperture blades. The aperture is slightly closed and as a result the bokeh-balls are octagons.
Creative Use of Bokeh
You can use bokeh as a creative tool to:
Isolate your subject
Remove distracting backgrounds
Add visual interest
Create mood and atmosphere
For example, shooting portraits at f/1.8 with distant lights behind your subject can produce beautiful background orbs.
Here is a backlit portrait shot with a shallow depth of field. The sun was setting behind the trees at the beach. With a narrow aperture the lines and shapes created by the trees were a visual distraction. So I had to open up the aperture to defocus the background and create a interesting almost magical looking background behind the model with lots of cat-eye bokeh. Opening up the aperture all the way while shooting directly towards the sunset created a blown out image so I had to use a flash at full power with a quick shutter to balance the light. We’ll get more into that when we talk about the Exposure triangle.
Why Aperture Matters for Proper Exposure
Aperture controls how much light enters your camera by adjusting the size of the opening in your lens. A wide aperture lets in more light, creating a brighter image, while a narrow aperture allows less light, resulting in a darker photo. In many situations, you can’t freely change your shutter speed or ISO without causing problems like motion blur or image noise. When that happens, aperture becomes your main tool for controlling exposure. Learning how to balance aperture with shutter speed and ISO is essential for getting consistent, well-exposed photos in different lighting conditions.
How to Use Aperture in Your Photography Workflow
Step 1: Decide Your Depth of Field Goal
Ask yourself:
Do I want background blur?
Do I want everything sharp?
Do I want subject separation?
Step 2: Choose Aperture First
Many photographers choose aperture first because it affects the look of the photo the most.
This approach is called “aperture priority.”
Step 3: Use Aperture Priority Mode
In Aperture Priority (Av/A) mode, you choose the aperture and the camera selects shutter speed and ISO automatically.
Although this may seem like a great way to shoot I strongly encourage you to avoid. It way better to shoot in Manual mode and learn how to set the proper exposure than to lean on the camera to do it for you. You won’t learn if the camera is doing all the work.
Step 4: Balance Exposure with ISO
If shutter speed becomes too slow because your aperture has become too small, raise ISO slightly to compensate.
Step 5: Review Focus and Sharpness
Zoom in and check whether your subject is properly in focus, especially when using wide apertures. This step only applies to people shooting with DLR camera or manual focus lenses. Mirrorless cameras usually have a subject tracking auto focus that becomes really helpful when you’re shooting at f1.2.
Best Aperture Settings for Common Situations
Portrait Photography
f/1.8–f/2.8
Landscape Photography
f/8–f/11
Street Photography
f/4–f/8
Product Photography
f/8–f/16
Group Photos
f/5.6–f/8
Low-Light Photography
f/1.8–f/2.8
cheat sheet - best aperture settings for common situations
Common Aperture Mistakes Beginners Make
Using Very Small Apertures Unnecessarily
Shooting at f/22 can reduce sharpness due to diffraction. Typically most lenses start to get softer around f/11. Stay tuned for a blog about diffraction coming soon where I’ll breakdown how and why it happens.
Ignoring Depth of Field
Not thinking about what should be in focus can weaken your composition.
Forgetting to Check Focus
Wide apertures require precise focusing. Always review your images.
Frequently Asked Questions About Aperture
What Is the Best Aperture for Beginners?
Start around f/5.6 and experiment wider and narrower to learn how depth of field changes.
Does a Lower f-Number Mean Better Quality?
Not always. Lenses are often sharpest around f/5.6 - f/8. Each lens has a sweet spot where it is sharpest. It’s best to play around with your lens to find it’s sweet spot.
Do Expensive Lenses Have Better Bokeh?
Usually, yes. Faster lenses with better bokeh are ofter harder to design and produce especially modern ones that are sharp wide open. That is usually reflected in the price of lenses.
Is Aperture More Important Than Shutter Speed or ISO?
All three are important. Aperture mainly controls depth of field which has an impact on style. But you can’t look at it as is one element more important than the other. Getting the correct exposure is about finding a harmony between the three elements.
Final Thoughts: Mastering Aperture for Better Photos
Aperture controls light, focus, and visual style in photography. Learning how to use it gives you creative control over background blur, sharpness, and mood. By understanding f-stops, depth of field, and bokeh, you can shape how viewers experience your photos.
Remember:
Wide apertures create blur and mood
Narrow apertures create clarity and depth
Bokeh is a creative tool
Balance aperture with ISO and shutter speed for correct exposures
Practice with different lenses and subjects to get a feel for what different apertures can do.
Mastering aperture completes your foundation in exposure and brings you closer to full creative control of your camera. Now that you have a practical understanding of ISO, shutter speed and aperture it’s time to move on to exposure theory. 🤓 Join me in the next post in this series as we learn about the exposure triangle and tie these pillars of exposure together.
