The exposure triangle
How can a simple triangle influence 90% of how well your image turns out?
What is the exposure triangle?
The exposure triangle is a relationship between the three elements that shape the exposure of your image - aperture, shutter speed, and ISO.
To understand the basics of the exposure triangle, you have to understand that it is not just about memorizing these three terms but grasping how the interplay between these three elements affects the overall look of your image.
Each element can be adjusted to achieve your desired creative outcome - whether you want to achieve a normal exposure, or overexposure or underexposure. Once you understand this, you gain the power to control the exposure in your images and add further creative expression to your images.
Let's examine each of these elements and their role in terms of exposure adjustments.
Aperture
Aperture refers to the diameter of the lens opening that permits light to reach the camera's sensor.
It's measured using a numerical scale, commonly known as "f-stops" such as f/1.4, f/2.8, f/4, f/5.6, f/8, f/16, f/22, and so on.
When it comes to aperture, each "stop" up or down effectively halves or doubles the size of the opening, consequently affecting the amount of light captured.
Wide apertures (larger f-stops)
The wider the aperture, represented by a smaller f-stop number (ex. f/2.8), the more light enters the camera.
For example:
Moving from f/4 to f/2.8 widens the opening size by half, resulting in twice as much light reaching the sensor.
Narrow apertures (smaller f-stops)
The more narrow the aperture, represented by a larger f-stop number (ex. f/16), the less light enters the camera.
For example:
Moving from f/2.8 to f/4 reduces the opening size by half, resulting in half as much light reaching the sensor.
How aperture affects depth of field
Apart from regulating the amount of light, aperture also plays a crucial role in controlling the depth of field.
A wider aperture (smaller f-stop) creates a shallow depth of field, where the subject is sharply focused while the background appears beautifully blurred.
On the other hand, a narrower aperture (larger f-stop) extends the depth of field, capturing more elements in sharp focus from foreground to background.
In essence, aperture not only influences the exposure of your image by controlling the amount of light but also allows you to unleash your creativity by manipulating the depth of field and shaping the visual impact of your photographs.
Shutter speed
Shutter speed refers to the duration for which the camera's shutter remains open when capturing an image.
Each increment in the shutter speed setting doubles or halves the exposure time compared to the adjacent setting. This allows you to precisely control the amount of light that enters the camera and tailor the desired effect based on the scene and your creative intentions.
Mastering shutter speed empowers you to capture crisp, static moments or create captivating blur, giving your photographs a distinct visual impact.
Faster shutter speeds
It's a straightforward concept to grasp: a faster shutter speed means a shorter exposure time, resulting in less light reaching the sensor. This shorter exposure effectively "freezes" any motion in the scene, capturing fast-moving subjects with sharp clarity.
For example:
A fast shutter speed like 1/1000s can freeze movements mid-stride or mid-jump.
Slower shutter speeds
Conversely, a longer shutter speed allows the shutter to remain open for a greater duration, permitting more light to reach the sensor.
This extended exposure time introduces a captivating phenomenon known as "motion blur." Moving subjects in the scene appear blurred in the direction of their movement, adding a sense of dynamism and artistic flair to your photographs. Depending on your artistic vision, motion blur can be a desired effect, enabling you to convey a sense of speed, fluidity, or the passage of time.
For example:
A slow shutter speed like 1/15s can produce a motion blur in subjects with moderate modement like people walking or flowing water in stream.
ISO
ISO determines the sensitivity of the camera's sensor or film to light.
While the concept remains the same between film and digital cameras, in the case of a DSLR, it pertains specifically to the sensor setting.
Lower ISO values
In essence, a lower ISO number indicates lower sensitivity to light, suitable for well-lit environments or when photographing under bright midday sun.
In such situations, opting for the lowest available ISO setting, such as ISO 100 or 200, ensures that your images maintain optimal clarity and minimize the presence of digital noise.
Higher ISO values
Conversely, in poorly lit scenes or situations where light is limited, higher ISO settings become necessary to compensate for the reduced light.
Increasing the ISO sensitivity, such as ISO 800, 1600, or even higher, allows the camera to capture more light, resulting in properly exposed images.
However, it's important to note that higher ISO settings often introduce a common challenge—digital noise. This unwanted speckling or spotting can affect the overall quality and sharpness of your images.
Take note!
Each camera has a different ISO threshold in which noise may start to become apparent. It's important you know this threshold so you can avoid lots of digital noise in your images! If you don't know what it is, a quick search online will provide you with your answer!
It's worth mentioning that high-end cameras generally perform better at handling noise issues at higher ISO settings. These cameras employ advanced technologies and improved sensor capabilities to mitigate noise problems, allowing for cleaner and more detailed images even at elevated ISO levels.
Understanding ISO sensitivity empowers you to adapt to various lighting conditions, striking a balance between capturing well-exposed images and managing digital noise.
Examples of balancing the exposure triangle
Let's take a look at some example scenarios so I can show you how each element of the exposure triangle would change in order to capture a well-exposed image. Please note that these are just example scenarios and not hard-set rules for each setting. I just want to give examples of scenarios I've been in.
Portrait photography
Let's say you're photographing a portrait session in a well-lit outdoor setting. To achieve a shallow depth of field and create a pleasing background blur, you set a wide aperture (low f-stop number) like f/2.8. Since your subject is not in motion, you can opt for a moderate shutter speed, perhaps around 1/125s, to ensure sharpness. Finally, you adjust your ISO to the lowest setting possible, such as ISO 100 if you're shooting during daytime to maintain optimal image quality in ample light.
Action/sports photography
Let's say you're capturing fast-paced sports action on a bright, sunny day. To freeze the action, you select a high shutter speed, such as 1/1000s, to ensure sharpness and capture the decisive moments. To maintain a reasonable depth of field, you choose a moderately narrow aperture, like f/5.6. Since lighting conditions are favorable, you set a low ISO, such as ISO 200, to minimize noise.
Night photography
Let's say you're photographing a captivating cityscape at night, where you want to capture the lights and the movement of traffic. To allow for an extended exposure and capture light trails from passing vehicles, you set a slow shutter speed, such as 10 seconds (you'll need a tripod). To ensure a reasonable depth of field, you choose an aperture like f/8. Due to low-light conditions, you increase the ISO to a higher setting, perhaps ISO 800, to properly expose the scene while managing noise.
Landscape photography
Let's say you're exploring a breathtaking landscape during golden hour, with soft, warm light casting a beautiful glow. To maximize the depth of field and ensure sharpness from foreground to background, you set a narrow aperture like f/16 or even f/22. Since your subjects are not in motion, you can use a moderate shutter speed, such as 1/60s (you'll need a tripod). Given the favorable lighting conditions, you select a lower ISO, like ISO 100 or 200, to maintain image quality.
Importance of the exposure triangle
Now that you know the basics of the exposure triangle, let's examine why it's important to learn about it.
Achieving proper exposure
The first and most important reason why you should understand the exposure triangle is to achieve proper exposure. Understanding how aperture, shutter speed, and ISO sensitivity work together will allow you to control and achieve the proper exposure in your images. This will ensure your images are neither too bright nor too dark.
Creative control
The second reason it's important to learn about the exposure triangle is for creative control. For example, if you want to have a slow shutter speed for a motion blur look, you will need to know how that will affect your ISO and aperture settings. Since all three elements affect one another, knowing how they all work together will allow you to achieve creative effects such as freeze-frame looks, motion blur looks, bokeh looks, etc.
Conveying emotion and atmosphere
The third reason it's important to learn about the exposure triangle is that it will allow you to further convey emotion and atmosphere in your images. For example, if you use a shallow depth of field with a wider aperture (such as f/1.8) you can blur the background and isolate a subject.
Here's another example, if you use a faster shutter speed such as 1/1000s you can freeze a moment of action. Each creative choice you take can add further emotion and atmosphere to your images but you can only make these choices by controlling all three elements of the exposure triangle.
Problem-solving in challenging lighting conditions
The fourth reason it's important to learn about the exposure triangle is that you will be able to solve problems in challenging lighting conditions. For example, let's say you're in a low-light environment such as a nightclub taking photographs. You will need to bump up your ISO settings but doing this will affect your shutter speed and aperture as well - so knowing how all three elements interact with one another is important.
Technical mastery
The fifth and final reason it's important to learn about the exposure triangle is that you will gain further confidence as a photographer in your technical abilities. Just like learning any skill, understanding how your camera operates and how light interacts with the sensor, as well as knowing how to manipulate settings to achieve a desired image will give you confidence. This confidence will allow you to confidently explore other various photographic techniques such as double exposures, different genres, and other creative photography techniques.
Final thoughts
In conclusion, the exposure triangle may seem confusing at first, but once you understand the three elements and how they work together, it becomes easy! Make sure you take the time to fully grasp each element and you'll be a master of the exposure triangle in no time!