A beginner's guide to depth of field

First published:
October 12, 2020
February 12, 2024

A beginner's guide to depth of field

First published:
October 12, 2020
February 12, 2024

Cover image by Kav Dadfar

Depth of field is one of the most powerful tools that you have in your photography arsenal. So, it is important to understand what it is and how you can use it in your photography

Camera on a tripod overlooking a rocky coast
Depth of Field is one of the fundamental pillars of photography. Not only is it of vital importance in helping a photographer capture the photos that they want to take. But it also offers a wealth of creative opportunities to help your photos stand out

What is depth of field?

Depth of field is essentially how much of your image (i.e. distance in a scene) that appears sharp from the closest object to your camera up to the thing that is furthest away.

There are three main factors that influence your depth of field:

- Your focus distance from your subject

- The focal length of your lens

- Most importantly, your aperture or f/stop

In addition to these, things like camera sensor size and even how a photo is printed can also influence what our eyes perceive as an acceptable level of sharpness.

It also important to know that there isn’t a sudden change in sharpness within your depth of field. In other words, there will be a gradual change from sharp to unsharp within the photo (a term known as the “circle of confusion”).

The reason that this is important, is because it can be difficult to spot when looking at your photos on the LCD screen on the back of your camera. You may only notice it when viewing the image in a larger size on a monitor.

This is why it is important to understand depth of field and use it correctly in your photos.

Image of two figres photographed with varying aperture settings
Aperture from left to right: f/2.8, f/4.5, f/8, f/13, f/22.

See how the sharpness of the figure at the back decreases as the aperture gets smaller? This is due to the effect of the changing depth of field when the aperture gets smaller.

What influences depth of field?

As mentioned above there are various factors that influence the depth of field in your photo. So, it is important to understand some of the basics of these so that you can utilise depth of field correctly and effectively in your photos.

- Aperture  

When most photographers refer to depth of field, this is often what they think of. It is with good reason as the aperture on your lens has a big influence on the depth of field within your photo. The aperture works in a similar way to our pupils in that the bigger it is, the more light it allows into the camera.

Where aperture can get a little confusing is in selecting the right one for what you want to achieve. As a wide or large aperture is actually selected with a low f/stop number and it gives you a shallow depth of field. While a small or narrow aperture is selected with a large f/stop number for greater depth of field.

Diagram showing the different aperture ranges and and the width of the aperture
The lower the f stop, the wider the aperture. And the wider the aperture, the more light your camera will receive

So just to be clear…

Low f/stop = wide or large aperture which means shallower (or shorter) depth of field so only a smaller distance within your photo will be sharp

Large f/stop = small or narrow aperture which means greater (or longer) depth of field so a greater distance within your scene will be sharp.

- Distance

Now, it might be tempting to think that you can simply select a large f/stop (a small aperture) and ensure everything in your scene will always be sharp. Unfortunately, it’s not as simple as that as the distance between your camera and the subject also has an impact on the depth of field. A good example of this is if you have ever tried to take a close-up photo of something but even with a small aperture cannot get the entire object or scene in focus.

So, it is also important to know that the closer your camera is to the subject you are photographing, the shallower your depth of field becomes. In other words, if you want to extend that depth of field you need to move further away from your subject.

Camera on a tripod looking down at flowers

- Lens focal length

The third thing that you need to be aware of when it comes to depth of field is the focal length of your lens (i.e. how much you are zooming into the scene). This can be complicated to understand but as a rough guide, the longer your focal length is the shallower your depth of field becomes.

For example, imagine you are taking a photo using a 35 mm (full frame) camera at an aperture of f/4 of an object 5 meters away. At a focal length of 50mm the total depth of field (distance that would be an acceptable level of sharpness) will be 2.71m. Compare this to using a 100mm focal length and now your total depth of field will be 0.63m. Even though you are the same distance away and using the same aperture, your depth of field is shallower due to your focal length.

DSLR with a zoom lens overlooking a city

Top tip:

There are plenty of great apps that calculate this total depth of field. Download on on your phone and if you're unsure, refer to it before taking a photo.

Why is depth of field important in photography?

Aperture (which controls your depth of field) together with shutter speed and ISO combine to form the "exposure triangle".

These are the three main settings that determine how a photo will be captured. Your depth of field is an essential part of this in helping you be able to take the photos that you want to make.

Image of a rocky shoreline and castle on the Scottish coast
For landscape photos you would ideally want a greater depth of field so more of the elements of the scene are in focus.

Sometimes, you have no choice but to select a wide aperture to be able to allow more light to enter the camera - so that you can take a photo without using a tripod. At other times, you may choose to use a wide aperture for more creative reasons like wanting to blur the background in a portrait.

Either way, by understanding how depth of field works you will have more control over the photos that you take.

A reveller at Venice carnival
For things like portraits a shallow depth of field will help blur the background

How to select or change depth of field

To adjust your depth of field (without physically moving or changing lenses), look for the setting in your camera that changes the f/stop number. Keep in mind that whichever dial, or wheel changes the aperture might change depending on which mode (i.e. aperture priority, shutter priority, manual etc) you have selected. When you see a number with “F” before it moving, you know that’s what you are looking for.

Try to practice in selecting and changing the aperture quickly while you are looking through the viewfinder. The last thing that you will want to be doing is spending precious seconds trying to select the right thing when you have a fleeting moment in front of you.

A landscape scene as seen through an LCD screen on a DSLR
Keep in mind that in live view mode you may not see the “f” before the number

How to use depth of field more creatively

The great thing about depth of field is that it gives you an extra form of creativity. For example, selecting a very shallow depth of field when photographing objects or people can blur the background and make them stand out more. Or you can even take this further and use it creatively by for example focusing on a building with a shallow depth of field thus blurring the surroundings. Just be very careful to ensure that you are focusing on the right element in the photo when using a shallow depth of field.

Long exposure of a waterfall
You can also use the aperture setting to increase your shutter speed. By selecting a smaller aperture and thus increasing your shutter speed you can introduce motion blur in your photos. This is a great way to add some dynamism to your shots.
10 sec | f/16 | ISO 100


The examples in this article are just some of the uses of aperture or depth of field in photography. To gain an understanding of depth of field is an essential part of your photography journey and is something that will help you capture better images.

This beginners guide should get you started in understanding it... But the best way to really learn is to practice and experiment. So, get out there are start taking photos!

All images from Kav Dadfar.

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