Aperture in Photography. What it is and how to use it?

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Aperture is a fundamental concept in photography, yet one of the most important. 

Understanding it doesn’t have to be complicated. 

In this short article part of the series Photography basics, you’re going to learn what it is and how to use it in no time.

You’ll also get some useful aperture settings and examples of how to use it.

Learning what is aperture is crucial if you want to up your photography game. Today you’ll learn what the Aperture is, how it affects your images, how it impacts the highlights and the shadows, and also how it affects the Depth of Field. 

Before we jump straight into the details, let me quickly answer a few basic questions a lot of people have:

  • What is the aperture on a camera?
    The aperture of a lens is the size of the opening that allows light through into the camera body. 
  • Who to measure the aperture?
    It’s measured in f-stops (e.g. f/2.8 or f/22)
  • What does aperture do to a picture?
    The aperture affects the brightness and the Depth of Field in a photograph

Understanding this basic concept is the first step to get out of auto mode. It’s also important to know that together with Shutter Speed and ISO, it is one of the pillars of photography.

If you’re looking for a complete guide about how it works together with ISO, Shutter Speed and it affects the Depth of Field, you can also read my articles

How Does Aperture Work?

lens aperture

When shooting a photograph, your lens diaphragm opens up for a certain amount of time (exposure time), and it allows the light to hit the camera sensor to record the image.

The size of the lens opening is the aperture, and it’s measured in f-stops.

It’s necessary to know that mastering the use of it will allow you to improve your photos dramatically. 

Thanks to a wide-open lens, for example, you can obtain a shallow Depth of Field hence a beautiful bokeh (soft background). Viceversa, a narrow opening, will cause the Depth of Field to be longer and so to get a larger part of your image in focus.

Read the Bokeh Photography Tutorial for Beginners to learn how to obtain silky smooth backgrounds in your photos.


As I said, it not only affects the Depth of Field but also the exposure of your image.

Mastering the basics of photography means knowing how to set up the proper aperture value and knowing how it affects the depth of field.

A wide-open lens corresponds not only to a shallower depth of field but also to a brighter image. 

Viceversa, a narrow value will give you a darker image (and a more extended depth of field).

By adjusting your camera settings, you affect a series of circular blades inside your lens. The blades will narrow down and widen up, determining different opening, according to the values you choose.

A value of f/16 or f/22 create that interesting star effect when shooting bright spotlights, like city lights at night, as you can see in the image above. Or if you’re shooting landscapes, the sun will be an excellent subject to experiment. Best time of the day for this is either going to be sunrise or sunset.

narrow aperture

A wide aperture will cause a smooth background effect called bokeh.

Bokeh caused by wide aperture

Measuring Aperture: F-Stop

Let’s now introduce the concept of f-stop and how to measure aperture. Take a look at the following images.

Aperture, Depth of Field and Exposure

Here you can see how it affects the brightness and darkness of an image (exposure).

From left to right, as you can see, the initial value of f/2.8 will let in a lot of light. That’s a wide aperture. Moving forward, reducing the aperture reduces the brightness, and as you notice, the values on the second and last images are f/8 and f/22.

So the higher the f-number, the smaller the aperture, and the darker the image.

Camera Settings. How to Affect Depth of Field

In the following image, instead, you can see how it affects Depth of Field. Let’s see some settings:

On the left, the wide-open lens (wide aperture f/2.8) results in a shallow Depth of Field. The background is entirely out of focus. 

On the right, a small aperture (f/16) makes it so that the background is acceptably sharp as well as the foreground. In this case, you have a larger Depth of Field. 

There’s a lot more to say in regards to Depth of Field and how to master it with the knowledge of Hyperfocal Distance. Find more here The Best Guide to Understanding Hyperfocal Distance.

How to set different your camera properly? I recommend to abandon the auto mode of your camera and set it to Aperture Priority mode. It’s called A (or Av on Canon cameras). 

The Aperture Priority mode is a semi-manual mode with which you can adjust the aperture value, and the camera will automatically determine the correct shutter speed for a proper exposure. 

The Complete Guide to Camera Settings will walk you through the process step by step in case you need it.

Aperture Examples in Landscape Photography

In landscape photography, you want to make sure that your entire scene is in focus. For this reason, you will select a small aperture.

By setting your camera to aperture priority mode, the camera itself will take care of ISO and shutter speed. Here’s an example.
With a small aperture (f/20) I was able to get most of the image in focus.

Roys Peak NZ Olympus M.Zuiko 12-40mm f/2.8

Fast Lenses (Zoom and Prime)

Now that you know more about this fundamental concept, if you’re looking for a new lens check out these fast f/1.8 Prime lenses:

And some zoom lenses if you want more flexibility to compose your images.

Aperture, Video Explanation

I found this video on Fstoppers and I thought I might include it here if you want a nice graphical explanation of how aperture works.

As you can see in the video at:

0:13 Aperture is the hole in the lens through which light travels into the camera body and onto the camera sensor.

1:00 The diaphragm is the “iris” of the lens and controls the size of the aperture.

1:10 It is expressed in F-stops or F-numbers. Small f-stop = large aperture. Large f-stop = small aperture.

1:42 It has a direct impact on the Depth of Field: the area of the image that appears sharp.

2:20 Fast Lenses description. F1.4 to F2.8 are considered fast lenses.

2:55 Prime and zoom lenses (I’ve also written an article on prime and zoom lenses here for you)

3:40 How aperture affects ISO and Shutter speed

4:34 Set your camera to aperture priority mode

Further Readings

At his point, you know quite a lot about aperture. To master it, make sure to experiment with different values and scenarios and with different compositions

Exploring the menu of your DSLR or mirrorless camera and playing around with different settings is one of the most important things to do when learning photography. 

Read part 2 of my photography basic series: Understanding ISO
Read part 3 here: Photography Basics: Shutter Speed

Let me know in the comments below if you have any questions or need any help understanding how your camera works!

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