Changing Aperture on the Sony a7iii (Easy!)

Hey folks, this is going to be a quick and concise guide on how (and why) to change the aperture on your Sony a7iii.

Do note that while this post is specifically targeting the a7iii, it’s applicable to any other full frame Sony camera.

Additionally, we’ll touch on what F-stop actually means along with my suggestions for the best bright aperture lenses.

Let’s dive in!

photo of lens aperture
Behold: a generic photo of aperture blades in a lens.

How to change aperture on the Sony a7iii?

Set Mode Dial to “A”

To start, we’re going to want to spin the mode dial on the camera over to the “A” position.

This stands for aperture priority.

What this means is that the camera will automatically adjust every other setting (like shutter speed and ISO), but will still allow you to change the aperture manually.

Adjust Aperture

Now, you can change the aperture by spinning either of the rear dials/wheels.

Do note that if you’re shooting in manual mode, that one of the dials will control shutter speed while the other will control the aperture.

However, if you’re in “A” mode, both dials should just change the aperture.

What is aperture?

So what exactly does “aperture” mean?

To put it simply, aperture is the “eye” of your camera lens.

Opening the eye lets more light in, while closing the eye lets less light in.

If you look closely at your lens, you’ll see the aperture (or “eye”) opening and closing as you adjust the aperture setting on your camera.

As the blades “retract”, the aperture opens up, letting in more light. As they tighten, the aperture gets smaller, allowing less light in.

What is F-stop?

Now, you may have also heard the term “F-stop” being thrown around.

F-stop may sound complicated, but it’s the ratio of the lens focal length in relation to the aperture “hole”.

To put it much more simply, F-stop is pretty much just a numerical value to help photographers understand how large their aperture is.

aperture blades in lens
F-stop is just a term used to measure the size of the aperture opening.

When someone says, “shoot with a wide/large F-stop”, they actually mean shooting with a low number, like F1.8.

On the flipside, a “small/tight” F-stop can mean something more along the lines of F16 or F22.

Why would I want to change my aperture?

Depth of Field (Background Blur)

Subject Isolation

So, when should you change your aperture?

The first reason you’d want to change your aperture is if you want to create depth of field, also known as background blur.

Adjusting your depth of field opens up a lot of creative elements.

When taking pictures of people, you’ll generally want a blurred background in order to create a sense of subject isolation (although there are plenty of exceptions to this rule).

This can easily be accomplished by opening up your aperture to something wide, such as F1.8.


In addition, shooting at wide apertures creates a visual effect known as “bokeh” (the pronunciation of this word is… up for debate).

To put it simply, bokeh is the way a lens renders out-of-focus points of light.

It has all sorts of artistic potential, from emphasizing subject isolation to intentionally blurring lights in the background for dramatic effect.

More in Focus

Now, on the flipside to all of this, there are situations where you’d want to “stop down” (tighten) your aperture.

A tighter F-stop allows for the scene to be more in focus due to more light hitting the camera sensor.

mountain with flowers
Stopping down (tightening) your F-Stop allows you to capture a lot more detail.

As an example, you’ll generally want to tighten your aperture when shooting something like landscapes or cityscapes.

This way, you’ll ensure that your entire scene is in focus and sharp.

Do keep in mind that pushing your aperture higher (especially in low light) will often require you to compensate with increased ISO or a longer shutter speed.

Low Light Situations

Speaking of low light, opening up your aperture is critical when shooting in dark conditions (night, indoors, astrophotography, and so on).

As we mentioned prior, opening your aperture allows more light into the lens, thus allowing you to shoot in darker environments.

Of course you could always increase your ISO in low light situations, but it’s generally best to adjust shutter speed and aperture first before resorting to pushing up your ISO.

night time street in paris
Opening up your aperture lets in more light in dark conditions.

What about lenses?

Primes vs Zooms

Even if you’re new to photography, you’ve likely noticed that lenses have certain apertures listed on them.

This is considered their “maximum” (or widest) aperture.

Zoom lenses tend to have tighter max apertures due to optical limitations from the zoom mechanism.

On the other hand, prime lenses are generally much brighter than their zoom counterparts.

For this reason, you’ll always want to have at least one prime lens in your kit at all times, as it’ll allow you to work with low light and other wide-aperture creative pursuits.

My Lens Suggestions

If you’re still shopping for lenses, I have a few wide aperture primes I can personally vouch for.

I’ll list them below (different focal lengths).

Sony FE 20mm F1.8

First up on the list is a wide-angle lens. The Sony FE 20mm F1.8 (affiliate link) is an excellent wide-angle lens with a bright aperture. You’ll get top-tier sharpness, a robust build, fast autofocus and great low-light performance. I recently took it on an epic weekend roadtrip, so make sure to check out my full review on it.

Sony FE 50mm F1.8

The Sony FE 50mm F1.8 (affiliate link) is an excellent low-budget lens for any a7iii shooter. It’s known as the brand’s “nifty fifty” (cheap 50mm prime lens) and it performs spectacularly.

Expect razor sharp images, quick autofocus, and a bright max aperture.

If you’re looking to buy your first prime lens for your Sony camera, make it the 50mm F1.8. It’s very, very budget friendly.

I’ve actually owned this lens for about a year (came with my camera) and yet I still haven’t reviewed it. It’s been a great (and budget-friendly) lens though, so expect a review soon!

Sony 85mm F1.8

Finally, if you’re looking to capture tighter photos (like portraits), consider the Sony 85mm F1.8 (affiliate link).

It renders bokeh beautifully and creates incredible subject isolation. It’s also razor-sharp and pretty budget-friendly.

I personally spent a lot of time using this lens so I can certainly vouch for it. It’s awesome!


So, now that you know the basics about aperture, it’s time to get out there and practice!

My best advice would be to just grab your camera and get outside.

Play around with your aperture settings and watch as backgrounds blur in and out.

Adjust focus while pointing the camera at bright lights and see how your lens renders bokeh.

string lights in hand
The best way to learn aperture is to get outside and practice!

If you’re looking to dive even deeper into mastering your camera’s manual controls, check out my a7iii-specific guides on both shutter speed and ISO.

Thanks for reading!

2 thoughts on “Changing Aperture on the Sony a7iii (Easy!)”

  1. Am a senior knew to this new-age tech stuff.
    Found this site amazingly info prone for someone with my dirth of technical know-how. And really easy to follow – which the instructions that come with my Sony a7iii were not so simple – and hard to read – too small print
    So thanks and
    “Good Luck with all your other future ‘Endeavours’ or ‘Projects”

    • That makes me so happy to hear! Even though I’ve been doing photography for about a decade, I try to structure my articles from a beginner’s perspective. I’m glad it helped. 🙂

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