What you should know about Aperture

Aperture, one of the most important settings of your camera!

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Camera settings

As we spoke in previous articles, Aperture is one of the 3 components of the exposure triangle, with ISO and Shutter Speed. Learning what is aperture and how to use it is a great way to improve your photographs. Indeed, besides the fact it can make your image brighter or darker, it has a huge creative effect by changing the depth of field of your photo. In other terms, it adds depth to your captures! If you want to know more, you can read this article about Depth of Field: (coming soon)

So, with no further ado let’s talk about Aperture!

What is the aperture of your lens?

An easy way to remember the function of an aperture is to think of it like the pupil of an eye. What does the pupil of an eye do? It gets broader or narrower to adapt the amount of light getting into your eye. When it’s bright the pupil shrinks (let less light into your eye) and if it’s dark the pupil expands to let more light in. The aperture of your camera works the same way; you can open it or close it as you wish!


How Is Aperture measured?

For beginner photographer, it starts to be confusing when the numbers come into play. Indeed, a small number like f/1.8 means a wide aperture (and a lighter picture), while a large number like f/22 indicates a narrow one (and a darker photo).

Because pictures speak louder than words, let’s have a look:


The aperture is expressed as follow, “f/n” (n being a number).

When you are shopping for lenses, you can see this “f/n.” Here are some examples:

Let’s take the Canon EF-S 18-55mm f/4-5.6 for example. The 18-55mm indicates the focal length of this lens. The f/4-5.6, on the other hand, indicates the aperture range this lens is capable of.

For example, if you had the lens zoomed all the way out to 18mm then the minimum aperture you could set would be f/4 (max opening).

If you were to zoom all the way in to 55mm, then the minimum aperture you could get would only be f/5.6.

I know it can be confusing when starting photography, but the more you practice, the more natural it flows in your head!

When you see a lens with only one number like f/2.8, that means:

– On a zoom lens, that the lens can stay wide open at 2.8 at any focal length; They are great lenses especially in low light condition, but they also are the most expensive lenses.

– the lens is a prime lens (no zoom)

If like me you are a Canon user, here you can have a look at the different lenses they offer “Canon EF Lenses.”

Like I said at the beginning Aperture also control the Depth of Field, allowing you to add a creative effect to your pictures.

What is the depth of field?

Simply put, it is the area in focus – that appears sharp – in your picture. Take these images for example:

The wider the aperture, the shallower the Depth of Field; This means a clear subject and a blurred background. Contrariwise when you choose a small aperture (big number) the all picture is in focus.


Choosing the right Aperture

How open you have your aperture is up to the style of photography you are going for. Indeed, portrait photographers tend to use shallow Depth of Field to make the model pop out of the background (see SpongeBob f2.8).

Landscape photographers use most of the time smaller aperture to get the all scenery sharp (see SpongeBob f/10).

It is essential to set your shutter speed to the ideal number for your style of shooting, then adjust the f/stop and your ISO.

Manual mode allows you to set the shutter speed, ISO and aperture all by yourself. However, if you are a beginner and you want to get used to aperture without having to think about the other settings you can use your camera “Aperture priority mode” (A or Av on your camera wheel) which allows you to set the shutter speed, while the camera does the rest.

Here’s something you can practice right now

As mentioned in the ISO and Shutter speed tutorials, the best way to get to know your camera’s settings is to practice.

A fun way to get to know your camera’s aperture and your lenses depth of field is to place a subject on a flat surface with something (s) in the background. Open your aperture all the way by setting it to its lowest setting. Snap a few pictures and take a look. Is the subject in focus with the background slightly blurred?

Now close the aperture significantly by setting it to about f/10 or higher and snap a few pictures again. Take a look. Is a majority of the photo in focus this time?


Precaution to take when setting your Aperture

Although aperture gives you more creative control to make images, here are some precaution you should take into account.

– Using a wide aperture can really make your subject pop from the background; however, it is harder to get sharp shots. When using an f/2.8, take care that your camera autofocus, focuses on the right point! Here you can learn more about “manual focus vs. autofocus.”

– How far is your subject also plays a role in the depth of field. Indeed, the closer the subject the blurrier the background.

– The kind of lens also plays a role. For example, telephoto lenses amplify the depth of field. A blurry background that you can obtain with an f/2.8 on a wide-angle lens could probably be achieved with only an f/4 on a telephoto lens.

I will release an “Ultimate guide about Depth of Field” soon, and although it looks complicated when you first start, once again, the more you train, the more you improve. Aperture really is a crucial piece of the puzzle to achieve striking images!

You want to have a nice blurred background, the 50mm f/1.8 is a fantastic, yet cheap lens that every photographer should have.