When you are starting out as a photographer the first thing you need to learn is the exposure triangle. Possibly second to your camera’s buttons, but it’s just as important to master.
I’ve made learning the exposure triangle for beginners a very simple process. It will make the difference between a picture that needs help in editing to one that’s almost perfect in camera every time. I say almost because the camera itself is not a perfect device – I’ll explain why later.
What is the Exposure Triangle?
The exposure triangle has 3 foundations – aperture, shutter speed and ISO. Each of these pillars can be changed to different levels in any camera with full manual controls. It’s getting the balance of all these foundations right to create a well-exposed photo.
When you change the settings of either aperture, shutter speed or ISO it will make your photo brighter or darker (amongst other things).
Unfortunately, this is where photography stops being logical. You’d think moving up a scale would make the shot brighter – this is only true with one of the elements – ISO. Instead, moving down the scales of shutter speed and aperture brightens a shot too. This is where photography can get confusing for beginners so bear with me.
What Makes a Good Exposure?
To understand how to get good exposure in a photo you need to know what ‘good’ looks like. This is speculative at best, and again another grey area of photography. You may want your image to be intentionally bright and ‘overexposed’ so it’s a personal judgment to assess what ‘good’ is.
But the camera can help you get a good standard to begin with. On the back screen of your camera or in the viewfinder you’ll see a little exposure scale ranging from -3 to +3. The aim of setting your exposure is to keep the dial at 0. This requires you to change the settings of shutter speed, aperture or ISO to do so.
Having the exposure scale at 0 will allow the camera to capture the best possible range of detail in the bright and dark areas in one shot. There are times that the camera may not do a good enough job in your opinion and you’ll need to take multiple shots at different settings and blend them all together. This is called bracketing.
How to Use the Exposure Triangle for Beginners
Figuring out how to use the exposure triangle to get the best-looking shot isn’t difficult once you’ve seen it in action, so pay attention.
The settings of each of the 3 foundations – aperture, shutter speed and ISO can be changed independently to balance out the other.
They are all governed by their own scales and while the units of measurement sound different they all measure light in the same amount.
What is the F/Stop Scale?
Aperture is guided by F/stops. This denotes the side of the hole letting the light through the lens. The bigger the number the smaller the whole – backward I know! The F/stop scale starts at F/1.4 for most photographers (but you may see it go lower) and ranges up to F/32 (again can go higher).
Here’s the full F/stop scale;
1.4 2 2.8 4 5.6 8 11 16 22 32
*You’ll discover half and third stops in between each of these full F/stops too.
Moving upwards from any full F/stop means the size of the aperture in the lens halves, resulting in a darker shot.
For example, switching from F/8 to F/11 means the shot is half as bright. Conversely moving from F/11 to F/8 means the aperture gets twice as big and the shot becomes twice as bright.
It doesn’t seem logical to make the big numbers represent a smaller aperture size. But if you understand this irregularity then you’ve won half the battle in understanding the exposure triangle.
How to Understand Shutter Speed
Shutter speed is very similar to the aperture in that it’s governed by a scale. This scale isn’t based on the size of a hole, it’s the length of time that the camera’s sensor is left exposed to light.
This length of time is either whole seconds or fractions of a second. Here is an example of the full ‘stops’ on the shutter speed scale (again you may encounter more fractions on your camera);
30 secs 15 secs 10 secs 5 secs 2 secs 1 sec ½sec
1/4th 1/8th 1/16th 1/30th 1/60th 1/100th 1/125th 1/200th 1/400th 1/800th 1/1000th 1/2000th 1/4000th 1/8000th
The longer shutter doors are open, leaving the sensor exposed to light, the brighter the photo. Therefore a shutter speed of 30 seconds would produce a brighter photo than a shutter speed of 15 seconds. The shorter the length of time the darker the photo would be.
How to Balance an Exposure?
Every time your shutter speed doubles or halves then the amount of light reaching the sensor doubles or halves respectively – i.e. moving from 1/100th to 1/200th halves the exposure time making the photo darker.
Hopefully, it’s starting to hit home how you can use shutter speed and aperture to create a good exposure. If you brighten your photo by one ‘stop’ on your shutter speed you can reduce the size of your aperture by one ‘stop’ to retain the same amount of light. Let’s see that in numbers;
Imagine these camera settings made a great exposure;
F/8 and 1/200th
Now if I made the aperture bigger by one stop (which would brighten the photo) I’d need to reduce the shutter speed by one stop to keep the same amount of light reaching the sensor. Therefore the settings below would also get the same exposure;
F/5.6 and 1/400th
I’ve doubled the amount of light coming through the aperture but halved the time the sensor is exposed for. Basically counteract each other to reach the same exposure.
Based on this process you’ll be able to change aperture or shutter speed by numerous stops to make the same exposures.
F/8 and 1/200th = F/5.6 and 1/400th
F/11 and 1/1000th = F/5.6 and 1/4000th
F/4 and 1/60th = F/8 and 1/15th
Unfortunately, there is no universal camera setting that beginner photographer should know to make a great exposure. Light is different in all conditions so you just need a bit of trial and error to begin with.
What is ISO?
ISO is the third pillar of the exposure triangle and works in the same way as shutter speed and aperture. It’s helpful to have 3 elements to play with when setting your exposure for two reasons;
Sometimes you may not want (or are able to) change other settings any further (i.e. you may have maxed out your shutter speed and/or aperture and your shot is still too dark). You need 3 sides to make a triangle anyway!
What Does ISO Do?
ISO controls the sensitivity of your digital sensor. This used to be called film speed back in the days of 35mm cameras. Fortunately, the ISO is super simple and doesn’t relate to size or length of time.
Here’s the full scale (again there may be more options on your camera);
50 100 200 400 800 1600 3200 6400 128,000 256,000
Basically, the numbers just keep doubling. Every time you double the ISO level you are doubling the sensitivity of the sensor. Halving the level halves the sensitivity (making the photo darker). Simple really!
In the same way, we looked at examples with aperture and shutter speed let’s look at how we can create the same levels of exposure with ISO thrown in as well.
Let’s pretend the settings below make a brilliant exposure;
F/8 1/200th 400 ISO
You could also reach the same level of exposure with these settings too;
F/5.6 1/200th 200 ISO
As the aperture doubles by one stop (making the shot brighter) the ISO halves by one stop to darken the shot. The shutter speed hasn’t changed.
Exposure Triangle Advanced Task
If you really want to take on a challenge you can change all 3 camera settings like this;
F/8 1/200th 400 ISO
These settings would deliver the same exposure as the new settings below;
F/4 1/400th 200 ISO
I’ve changed the aperture to be two stops bigger and therefore reduced the shutter speed and ISO by one stop each to counteract the aperture. That wasn’t so difficult now was it?
What are Half and Third F/Stops?
If you think of these settings as ‘stops’ and make sure you’re compensating the changes on one for another you’ll never go far wrong. What will complicate the process is the half and third stops that you’ll encounter.
As modern digital cameras get better and more adept to micro changes in shutter speed, aperture and ISO there’ll be more and more stops to choose from. These are known as half or third stops. They fall in between the ‘full’ stops on your aperture, shutter speed and ISO scales.
These will only change the amount of light by a smaller fraction (half or a third). This can be confusing when you’re looking at the back of the camera and wondering why your shot is only a tiny bit brighter/darker. This will be because your next stop is only a half or third.
To make the exposure triangle easier as a beginner, learn what the full stops are to begin with. Once you recognize them on the screen you’ll know which settings to change to.
Other Ways to Improve Exposures
I said back at the start that learning the exposure triangle for beginner photographers will get you close to a great-looking shot. It may not get you 100% of the way there every time. Why is this?
It’s because of the dynamic range. That’s how much detail can be seen in the shot from the dark to light areas and everything in between.
What is Dynamic Range in Photography?
Our eyes can detect around 8 F/stops of dynamic range in most conditions – a camera can only detect 1 stop in a single exposure. Therefore how we see a scene can look very different to the camera.
This can make beginner photographers frustrated that they aren’t using their camera right – which isn’t true. But there are things you can do with your camera to get you closer.
Learning more about AEB (auto exposure bracketing) and HDR on your camera will allow you to take shots closer to the exposure you see with your eye. The higher grade the camera generally speaking the better the dynamic range performance.
It’s possible to shoot great shots with any camera if you understand the exposure triangle and you’re not afraid to use manual mode.
Did You Enjoy This?
Let me know what you thought about this exposure triangle for beginners’ guide. Has it helped your photography? I’d love to know.
Stephen Walton Photography Workshops 
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