If you’re just getting started with photography, one of the first things you will come across is the Exposure Triangle.
It sounds complicated at first, but it is actually a simple way of understanding how your camera controls the brightness of your photographs.
The Exposure Triangle is made up of three settings:
- Aperture
- Shutter Speed
- ISO
These three settings work together to control the exposure of your photograph. Changing one will usually mean you need to adjust another if you want to keep the same overall exposure.
Once you understand how they work together, you’ll have much more control over your camera instead of simply relying on Auto mode.
What Is Exposure?
Exposure simply means how bright or dark your photograph is.
A photograph that is too bright is called overexposed.
A photograph that is too dark is called underexposed.
Ideally, you want an exposure that records the scene correctly while still giving you the creative look you want.
Your camera controls exposure using:
Aperture + Shutter Speed + ISO
Think of them as three different controls that work together.
The Three Parts of the Exposure Triangle
1. Aperture – How Much Light Enters the Camera
Aperture is the opening inside your lens.
It works a little like the pupil of your eye. A larger opening lets more light into the camera, while a smaller opening lets in less.
Aperture is measured using f-numbers, such as:
- f/1.8
- f/2.8
- f/4
- f/5.6
- f/8
- f/11
- f/16
One confusing thing for beginners is that a smaller f-number means a larger aperture.
For example:
f/1.8 = large opening
f/16 = small opening
Aperture also controls depth of field
This is one of the most important creative uses of aperture.
A wide aperture such as f/1.8 or f/2.8 can give you a blurred background.
This is great for:
- Portraits
- Wildlife
- Flowers
- Detail photographs
- Isolating a subject
A smaller aperture such as f/8 or f/11 keeps more of the scene in focus.
This is useful for:
- Landscapes
- Buildings
- Architecture
- Groups of people
- City photography
Easy way to remember it
Low f-number = more light + more background blur
High f-number = less light + more of the scene in focus
2. Shutter Speed – How Long the Camera Takes the Photo
Shutter speed controls how long your camera’s shutter remains open.
It is normally measured in seconds or fractions of a second.
For example:
- 1/1000 sec
- 1/500 sec
- 1/250 sec
- 1/125 sec
- 1/60 sec
- 1/30 sec
- 1 second
- 5 seconds
A fast shutter speed lets in less light but can freeze movement.
A slow shutter speed lets in more light but can create motion blur.
Fast Shutter Speeds
Fast shutter speeds are useful when photographing movement.
For example:
1/1000 sec
could be useful for:
- Surfing
- Birds
- Wildlife
- Sports
- Cars
- Fast-moving subjects
For my own surf photography, shutter speed is particularly important because waves and surfers can move incredibly quickly.
If your shutter speed is too slow, you can end up with a blurry photograph.
Slow Shutter Speeds
Slow shutter speeds can be used creatively.
For example:
1 second
can create movement in:
- Water
- Clouds
- Traffic
- People
- Light trails
This is where you can start getting creative with photography.
For example, photographing traffic at night with a slow shutter speed can produce those familiar light trails from the cars.
3. ISO – How Sensitive the Camera Is to Light
ISO controls how sensitive your camera’s sensor is to light.
Common ISO settings include:
- ISO 100
- ISO 200
- ISO 400
- ISO 800
- ISO 1600
- ISO 3200
- ISO 6400
A lower ISO generally gives you the cleanest image.
A higher ISO allows you to photograph in darker conditions, but it can introduce noise/grain into your photograph.
Low ISO
ISO 100 is great when you have plenty of light.
For example:
- Sunny days
- Landscapes
- Architecture
- Studio photography
High ISO
Higher ISO settings are useful when you don’t have enough light.
For example:
- Indoor photography
- Night photography
- Wildlife
- Events
- Sports
How the Three Settings Work Together
This is where the Exposure Triangle starts to make sense.
Imagine you’re photographing a surfer.
You want to use:
1/1000 sec
because you want to freeze the movement.
The problem is that a fast shutter speed reduces the amount of light entering the camera.
You therefore have two main options.
Option 1 – Open the aperture
You could use something like:
f/4
instead of:
f/8
The larger aperture allows more light into the camera.
Option 2 – Increase ISO
You could increase your ISO.
For example:
ISO 400 → ISO 800
This makes the sensor more sensitive to the available light.
So changing one part of the Exposure Triangle often means adjusting another.
The Exposure Triangle in Simple Terms
Here’s the easiest way I remember it:
| Setting | Main Job | Creative Effect |
|---|---|---|
| Aperture | Controls light | Background blur/depth of field |
| Shutter Speed | Controls time | Freezes or blurs movement |
| ISO | Controls sensitivity | Affects image noise |
Think of it like this:
Aperture = Depth of field
Shutter speed = Movement
ISO = Noise
This is much more useful to remember than simply thinking about brightness.
A Simple Example
Imagine you’re outside on a sunny day.
You start with:
ISO 100
f/8
1/500 sec
Your photograph looks correctly exposed.
Now you decide you want a blurry background.
You change:
f/8 → f/2.8
You’ve opened the aperture, allowing considerably more light into the camera.
The photograph will therefore become brighter.
To compensate, you could increase the shutter speed:
1/500 → 1/2000 sec
Now you’ve reduced the amount of time the sensor receives light.
You have changed the look of the photograph while keeping a similar exposure.
That’s the Exposure Triangle in action.
Why Beginners Often Get Confused
The biggest problem is that the numbers seem to work backwards.
For example:
Aperture
f/2.8 lets in MORE light than f/8.
Shutter speed
1/1000 lets in LESS light than 1/125.
ISO
ISO 1600 is more sensitive than ISO 100.
Once you understand those three relationships, everything becomes much easier.
Which Setting Should You Change First?
There isn’t one answer because it depends on what you’re photographing.
I normally think about the most important creative requirement first.
Photographing Sports or Surfing
Start with shutter speed.
Try:
1/1000 sec or faster
Then adjust aperture and ISO to get the exposure you need.
Photographing Portraits
Start with aperture.
For example:
f/1.8 – f/4
depending on the lens and how much of the subject you want in focus.
Then choose a suitable shutter speed and ISO.
Photographing Landscapes
Start with aperture.
Something around:
f/8 – f/11
is a good starting point.
Then adjust shutter speed and ISO.
Photographing Light Trails
Start with shutter speed.
You might be using:
1–30 seconds
depending on the effect you’re trying to create.
A tripod will normally be essential.
What About Auto ISO?
Don’t be afraid of Auto ISO.
It’s actually extremely useful.
Modern cameras are very good at controlling ISO automatically.
For example, when photographing surfing, you might set:
Shutter speed: 1/1000 sec
Aperture: f/5.6
and allow the camera to automatically adjust ISO.
This means you are controlling the two settings that matter most while the camera handles changing light levels.
Aperture Priority Mode
If you’re new to photography, Aperture Priority is a great way to learn.
On many Sony cameras this is:
A mode
or
A
You choose the aperture and the camera automatically selects the shutter speed.
For example:
f/2.8
The camera then chooses a suitable shutter speed based on the available light.
This lets you concentrate on depth of field while gradually learning how the other settings work.
Shutter Priority Mode
Shutter Priority is useful when movement is important.
On Sony cameras this is normally:
S mode
You choose the shutter speed and the camera controls the aperture.
For example:
1/1000 sec
This can be useful for:
- Surfing
- Sports
- Wildlife
- Birds
- Motorsport
Manual Mode
Eventually you may want to use Manual (M).
Manual mode gives you control over:
- Aperture
- Shutter speed
- ISO
This gives you maximum control but isn’t necessarily the best place to start.
I’d recommend learning what each setting does first rather than immediately trying to shoot everything manually.
The Exposure Meter
Your camera has an exposure meter that helps you judge whether your photograph is likely to be too bright or too dark.
You may see something similar to:
-2 -1 0 +1 +2
The middle is generally considered the camera’s suggested exposure.
However, don’t feel that you always have to keep it at exactly 0.
Sometimes you deliberately want a darker or brighter photograph.
Photography isn’t simply about making the meter read zero.
It’s about getting the photograph you want.
Exposure Compensation
Exposure compensation is another very useful feature.
If you’re using an automatic or semi-automatic mode and your photograph looks too dark, you can add positive exposure compensation.
For example:
+1 EV
If it looks too bright, you can use:
-1 EV
This is a really easy way for beginners to fine-tune exposure without having to manually change everything.
The Exposure Triangle Isn’t Really a Triangle
One thing worth remembering is that the Exposure Triangle is mainly a learning tool.
It isn’t a physical system inside your camera.
The three settings affect more than just brightness:
Aperture → depth of field
Shutter speed → motion
ISO → noise/image quality
That’s why choosing exposure is really about deciding which compromises you are happy with.
My Simple Beginner Approach
When I first recommend settings to someone learning photography, I suggest thinking in this order:
1. What am I photographing?
Is it:
- A landscape?
- A person?
- Wildlife?
- Surf?
- A building?
- Moving traffic?
2. What effect do I want?
Do I want:
- A blurred background?
- Everything sharp?
- Frozen movement?
- Motion blur?
3. Choose the important setting
For example:
Surf → shutter speed
Portrait → aperture
Light trails → shutter speed
Landscape → aperture
4. Adjust the other settings
Use the remaining controls to get the exposure you need.
Exposure Triangle Cheat Sheet
Aperture
f/1.4 – f/2.8
Lots of light
Strong background blur
f/4 – f/5.6
Good general-purpose range
f/8 – f/11
Less light
More of the scene in focus
f/16+
Very small aperture
Large depth of field, but image sharpness can sometimes decrease because of diffraction.
Shutter Speed
1/1000+
Very fast movement
1/500
Sports and action
1/250
General movement
1/125
General photography
1/60
Can work handheld depending on the lens and subject
1 second+
Creative motion blur/light trails
Usually requires a tripod for static subjects
ISO
ISO 100
Best image quality when there is plenty of light
ISO 400–800
Everyday photography
ISO 1600–3200
Low-light photography
ISO 6400+
Very low light, depending on your camera and how much noise you’re willing to accept
A Simple Exercise to Learn the Exposure Triangle
The best way to understand the Exposure Triangle is to actually experiment with it.
Take your camera outside and photograph the same subject.
Start with:
ISO 100
f/8
1/250 sec
Take a photograph.
Then change the aperture to:
f/4
Take another photograph.
You’ll notice that the photograph becomes brighter and the background becomes more blurred.
Now compensate by increasing your shutter speed.
Try:
1/1000 sec
Take another photograph.
Now compare all three photographs.
You will start to see that changing exposure isn’t just about making the photograph brighter or darker.
You’re changing the appearance of the photograph.
Don’t Worry About Getting It Perfect
When you’re learning photography, it’s very easy to get obsessed with finding the “correct” settings.
There aren’t really any universal correct settings.
The best settings depend on:
- The light
- Your subject
- Your lens
- Your camera
- The effect you want
- How much movement there is
The important thing is understanding why you’re changing a setting.
Once you understand that, you can start making decisions rather than simply copying camera settings from somebody else.
Final Cheat Sheet
If you only remember three things from this guide, remember these:
Aperture
Controls depth of field
Low f-number = more light + blurred background
Shutter Speed
Controls movement
Fast = freezes movement
Slow = creates motion blur
ISO
Controls sensor sensitivity
Low ISO = cleaner image
High ISO = more noise but useful in low light
And remember:
Aperture controls the look of the background.
Shutter speed controls the look of movement.
ISO helps you deal with the available light.
Once these three ideas start to become second nature, you’ll find photography becomes much easier — and you’ll be able to start getting the camera to create the image you have in your head rather than simply accepting whatever Auto mode gives you.
No responses yet