Aperture is just one element of the exposure triangle – the other two elements being Shutter Speed and ISO. Understanding Aperture will give you the ultimate creative control over your photos and in this post, we’ll go through everything you need to know about aperture and how to use it!
What is Aperture?
Aperture can be defined as the size of the opening in a camera lens that lets light through to the sensor – which is what captures the image in the camera body.
The aperture opening is adjustable so you can let either more or less light through to account for the brightness of your surroundings.
Changing the aperture does two things:
- controls how much light is being let in through the lens as mentioned above
- affects the depth of field
I’ll expand on these two points below.
How Does Aperture Affect Light?
Think of an eye for example. If you’re outside on a beautiful sunny day, your pupil will be small, but if you’re in a dark room, your pupil will open up and look large. This is your eye’s way of adjusting to the amount of available light so that you can see your surroundings to the best of your eye’s ability.
So basically, your pupils act like aperture does in a camera! To summarize:
bright surroundings = small pupil = closed aperture
dark surroundings = large pupil = open aperture
How Does Aperture Affect Depth of Field?
Depth of field is how much of the photo is sharp. If the entire photo is sharp, then it’s fair to say it has a large depth of field. If there is just a small slice of the photo that’s sharp, then it has a shallow depth of field.
A closed aperture (think small pupil) has a larger number, like F16, and will usually create a large depth of field. An open Aperture (large pupil) has a smaller number, like F5.6, and will usually create a shallow depth of field.
Out of the two photos above, guess which one was taken at an aperture of F5.6? If you said the photo of the bird, you’re correct! See how it’s just the small slice of the photo that’s sharp? That’s because the camera aperture was wide open at F5.6, creating a shallow depth of field with that beautiful bokeh.
Pro Tip: Bokeh is the quality of the blur in those photos with a dreamy soft background blur, like the background of the bird photo above. This would be considered good bokeh.
Check out the sketches below to help visualize how changing the aperture affects the depth of field:
Pro Tip: The slice of what’s in focus depends on where you focus your camera. In the sketches above, I was trying to show that I was focussing on the mushroom.
There are a few other factors that play a role in depth of field, like distance to subject and using different focal lengths. You can learn more about understanding focal lengths here.
How to Choose the Right Aperture
As mentioned above, changing the aperture does two things. It controls the amount of light being let in and it also affects the depth of field within your photo.
Choosing the right aperture can be looked at in both a technical and creative perspective.
To choose my aperture, I usually ask myself two questions:
- What does my scene technically require in terms of aperture?
- What sort of creative effect am I looking to apply to this photo?
Let’s dive in deeper below!
Technical Aperture Requirements of a Scene
This is really quite simple and it means is looking at the amount of light available in a scene to understand what aperture to select.
For example, are we outside on a bright sunny day or are we inside at a birthday party?
Now, think back to the pupil sketch above. On a bright and sunny day, the pupil will be very small to allow LESS light in. The same should be said for the camera aperture.
To give you an idea, I like to use an aperture between f/8 and f/16 when taking photos outside on a bright sunny day.
What about if we’re inside at a birthday party?
In that case, thinking back to the pupil again, the pupil will look more large in a dark lit scenario to let MORE light in. The same should be said again for the camera aperture.
I like to use an aperture between f/1.4 and f/5.6 when inside to ensure my photos are nice and bright. And on top of it, using an open aperture like f4 will result in a photo having that beautiful bokeh effect. Which works perfectly for birthday parties and also brings us to the next point!
Using Aperture Creatively
When analyzing a scene, the second question I like to ask myself is what sort of creative effect am I looking to apply to this photo?
The options are to either select an aperture that will result in a large depth of field (like f/16) or to select an aperture that will result in a shallow depth of field (like f/4).
Creatively speaking, I love using more open apertures like f/1.4 to f/5.6 for scenarios where I’ll be photographing people to really hone in on the facial expressions of that single person in the moment.
After we’ve grasped the basics of photography and we’re then able to use aperture and shutter speed together creatively, we can come away with some awesome photos like this one here:
After all, having creative control is one of the primary reasons we get into photography, am I right?
How to Set the Aperture in Manual Mode
In the cameras settings, Aperture is shown as “F#” (like F2 for example). I can change the aperture in manual mode a few different ways on my Canon 70D, but here’s my favourite way:
- make sure I’m shooting in manual mode
- use the scroll wheel by my right thumb. While rolling that wheel, whether looking through the eye piece or using the LCD screen, this number will change:
- scrolling the wheel left will make the number smaller, while scrolling the wheel right will make the number larger
Remember, a larger number like 16 is a more closed aperture (f/16). A smaller number like 4 is a more open aperture (f/4).
To help remember this, think of aperture numbers like fractions and replace the f with a 1. So then, f/16 becomes 1/16 and f/4 becomes 1/4.
Which fraction is bigger?
I hope you said 1/4! So f/4 (think 1/4) is a more open or bigger aperture than f/16 (think 1/16).
If you’d like to see the technical explanation of how aperture stops work, check out this post: understanding stops in photography.
You’ll need to cozy up with a nice cup of tea for this one! And if you do decide to have read, it will help clarify how aperture is measured and the numbers will finally make sense from this point on!
How to Set the Aperture in Aperture Priority Mode
When I want creative control over setting the Aperture in camera, I’ll usually be shooting in Aperture Priority Mode. To get to Aperture Priority Mode, I just twist my mode dial at the top of my Canon 6D Mark II until it’s set to Av like so:
Then, I use the scroll wheel by my right index finger to set my aperture. Scrolling left will give me a more open aperture like f/1.4 and scrolling right will give me a more closed aperture like f/16.
What I love about using Aperture Priority Mode is that I can focus solely on how I want to use Aperture creatively, and my camera will adjust the Shutter Speed and ISO to correctly expose the photo!
Now that you know how to adjust your Aperture in Manual and Aperture Priority Mode, here are some creative aperture photography ideas you can try!
Aperture Photography Ideas
Different apertures produce different results. Here are some aperture ideas you can try to gain more creative control over your photos! Let’s start with the most wide aperture and make our way to the most small aperture.
f/1.4 – Ultimate Bokeh
I love using an aperture of f/1.4 when doing product photography. It’s just enough to call attention to that one subject while blurring out everything else.
The photo above was taken hand held at 50mm, ISO 400, 1/160 sec, f/1.4. The key here is to ensure you’re focussing on the product that you want to be sharp because if you don’t, the depth of field is so shallow that it will likely end up blurry.
f/2.8 – Milky Way Galaxy
My absolute favourite way to use aperture in photography is to capture our beautiful Milky Way Galaxy.
The photo above is a 10 image panorama taken at 14mm, ISO 6400, 5 sec, f/2.8. Capturing a shot like this takes a bit of planning and I like to reference the Photopills Milky Way Planning Tutorial to help me get the shot!
If you want to add some excitement to your photography adventures, just try capturing the Milky Way. I’ll never forget how alive I felt when seeing the Milky Way core pop up on the back of my LCD screen, I hope you can experience the same!
f/5.6 – Adventure Time
When out and about with family or friends on a photography adventure, I usually leave my aperture on about f/5.6 in Aperture Priority Mode. The reason why is because whether it’s bright and sunny or cloudy, f/5.6 is usually good enough to ensure my shutter speed will be fast enough to result in sharp photos. Also, it’s a nice central ground to ensure that even if I didn’t nail my focus on my subject, they’ll still likely be sharp (rather than opening up the aperture to say 1.4 and risking a blurry subject).
This photo was taken handheld at 50mm, ISO 400, 1/200 sec, f/5.6
f/8 – Capture the Moon
The incredible amount of detail you can get of the moon with a telephoto lens is stunning. And not just jaw dropping, I mean tear jerking it’s so darn beautiful. The first time I saw this pop up on the back of my LCD screen I literally had to brace myself on my husbands arm to stop myself from falling over. I promise, no wine was involved.
This photo of the moon was taken on a tripod with a 600mm lens at ISO100, 1/250 sec, f/8. The trick here is to set a 10 second timer to ensure there is no camera shake. With such a long lens, it truly almost takes 10 seconds for the camera to stop shaking after you press the shutter button.
f/11 – Landscapes & Architecture
When my main focus is landscape or architectural photography, this is typically where I set my aperture to. With my 16-35mm lens, an aperture of f/11 results in a nice sharp photo from front to back.
This photo was taken on a tripod with camera settings of ISO 100, 1/60 sec, f/11.
This photo was taken hand held at ISO 200, 1/160 sec, f/11. Notice how the rocks and snow in the front are nice and sharp along with the mountain in the distance? Having an overall sharp photo like this without having to focus stack is perfect and an aperture of f/11 helped me to achieve this.
f/16 – Sunny Sixteen
To be honest, I don’t take many landscape photos at f/16 and I’ll explain why below, but if you’re looking to get that awesome sunburst look in your photos, adjusting your aperture to f/16 is the way to do it! Plus, it’s easy to remember too, just think of the Sunny Sixteen rule!
This photo was taken hand held at ISO 100, 1/60 sec, f/16. The trick here is to compose your scene where the sun is just peeking from behind an edge, like the rock above. This, in addition to setting your aperture to f/16 will give you that stunning sunburst effect!
You’re welcome!
Potential Aperture Problems
Dust and Water Spots
Although there are many great things we can do with aperture, there are also some negative effects we may experience with aperture as well. Let me explain.
Remember how I said I usually don’t take a lot of landscape photos at f/16? That rule for me applies to anything f/16 and smaller (like f/22).
The reason why is because smaller apertures like this result in so much of the photo being sharp, that it usually captures dust and water spots on my lens as well! Take a look at this crop of the sunburst photo:
Photos I take at f/16 usually result in a lot of post processing work where I spend way too much time removing dust and/or water spots. So, wherever I can, I’ll use a bit more of a wide aperture like f/11 or f/8 to mitigate this.
Apertures like f/22 and smaller also have another adverse affect to be aware of.
Know what it is?
If you said Lens Diffraction, you get a virtual high five!
Lens Diffraction
Lens diffraction occurs when light rays that are passing through your camera’s aperture begin to interfere with one another. As apertures get smaller and smaller, like f/16, f/22 and f/32, the photo taken looks less and less sharp. Sometimes, the photo can even look blurry and not in a desirable way.
In the photo taken at f/8 above, even though it’s been cropped in quite far, you can see the details in the central leaf. But in the photo taken at f/32, the sharpness in the central leaf has deteriorated. This is because at f/32, the camera is trying to squeeze light through such a small opening in the lens that the light ends up interfering with itself, causing some wavelengths of light to overlap and cancel out, resulting in a less sharp photo.
So, to avoid losing detail in my photos, I rarely choose an aperture smaller than f/16. For my landscape photos, I typically like to stay between f/8 and f/11 as this typically results in a nice sharp photo with a large depth of field.
Lens Aberration
Ever notice the corners of your photos aren’t exactly sharp? I often do in my astrophotos and the culprit is Lens Aberration.
Lens aberration is the deviation of light rays through the camera lens and it causes the objects in the photo to be blurred. In a perfect word, every point of light that hits the lens would focus to a single point on the sensor, resulting in a sharp photo. But because the glass in our lenses isn’t perfect, this isn’t the case.
Check out this example from one of my astrophotography shoots. This crop was taken from the far left top corner.
Notice how the stars start to change shape and look foggy? This is because at a wide open aperture like f/1.4, it’s letting in so much light at the edges that the light rays from the corners of my lens are starting to interfere with each other. Where as if I were to use an aperture like f/4, not as much light is being let in from the edges, resulting in much less visible aberration.
How then can we balance out the potential issues with Lens Diffraction and Lens Aberration? These two issues lie at opposite ends of the aperture spectrum and most lenses are sharpest right in the middle. So choosing an aperture like f/4 up to f/8 will likely mitigate the issues from both ends. Perhaps give this a try on your own lenses though as each one is different.
I still use apertures between f/1.4 and f/16 all the time. My choice depends on what the scene technically requires from me and what sort of creative effect I want my finished photo to have. I just know that if I stop down too much (like f/22) or open up my aperture all the way (f/1.4) that I can expect to see some issues in the finished photo.
Understanding Aperture Summary:
Just to ingrain this into your brain, a smaller number like F1.4 means the Aperture is more open. A large number like F16 means the Aperture is more closed. Remember, the smaller the F number:
- the more light you’ll let in
- the smaller the slice that’s sharp (creating a larger depth of field)
Understanding how to technically and creatively use aperture can result in some spectacular photos. I hope you can apply some of the aperture photography ideas shared in this post on your next photo adventure!
If you’re in the beginning stages of DSLR photography, make sure to check out our FREE 8 Essential Tips for DSLR Photography Beginners. It might just knock your socks off! Plus, there’s a little something special at the end.
These are the tips that gave me creative control over my photos. Now, I actually understand how to use my DSLR to get the feeling I want and capture the moment each and every time!
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Roy
Thank you for very in depth explanation of aperture-shutter speed and ISO. The diagrams certainly enhance the explanations. Found the article most interesting although I am not totally new to photography having used a 35mm Nikon F3 for many years in my work as an Information Officer in the Rhodesian Government for many years.
Using a DSLR has many similarities with the added advantage of being able to see the results on the LCD Screen. My main interest now is bird and nature photography.
I certainly enjoy reading your articles.
Claire
Thank you so much for your kind words Roy! You’re very welcome and I’m so happy to hear you enjoyed the article. Wow, what a career! There’s something very special about capturing nature on camera. I recently went out to photograph the blue herons with my telephoto lens. I didn’t have much luck with the herons but witnessed a couple of humpback whales breaching in the distance. I just sat and watched for about half an hour. Sure love the adventures cameras take us on.
Thanks again. It’s kind folks like you that make me enjoy writing so much.