The exposure triangle is a fundamental principle in photography. This statement is true for both digital and film photography. Three essential components are necessary to create an image: Aperture, Shutter Speed, and ISO. Sometimes, people call it the triangle of ISO, aperture, and shutter speed.

Exposure Triangle: Key Takeaways

• The three fundamental variables of the exposure triangle are aperture, shutter speed, and ISO.

• A camera's ISO determines its sensitivity to light. Increasing the ISO results in a brighter photo.

• The aperture refers to the size of the hole in the lens, and a larger aperture will make the photo brighter.

• The time the camera's sensor is exposed to light is called shutter speed. A longer shutter speed will make the photo brighter.

• An image's brightness or darkness, also known as its overall exposure, is determined by ISO, aperture, and shutter speed working together.

Let's examine the fundamental components in all types of photography, irrespective of the camera system used.

Before experimenting with your SLR camera's manual settings, it's essential to understand the Exposure Triangle. This will help you gain the confidence to explore non-auto locations.

To create an image in photography, it is imperative to understand the exposure triangle, which includes the ISO, aperture, and shutter speed. The holy trinity of photography consists of three essential elements for taking great photos.

Shutter Speed + Aperture + ISO = Exposure Triangle

Learning and understanding the Exposure Triangle is fundamental to basic photography.

The Exposure Triangle refers to the three essential components of a camera's exposure: ISO, aperture, and shutter speed.

The elements mentioned assisting in regulating the quantity of light that reaches the digital light sensor in the camera.

• The ISO refers to the standard unit for measuring the sensitivity of your digital camera to light.

• The aperture, which is the opening in the lens, is responsible for controlling the amount of light that enters the camera's digital sensor.

• The Shutter Speed refers to when the camera's shutter stays open while capturing a photo.

Aperture Is Like The Size Of A Window

Photography instructors frequently use the analogy of a window to explain the concept of the exposure triangle to beginners. To understand this analogy, picture a room with a window. The window has plastic shutters on the outside and a thin, semi-transparent curtain on the inside.

The size of a window's aperture affects the amount of light entering a room. A more significant aperture results in more light, while a more minor aperture results in less light and a darker space.

How Long Are The "Window Shutters" Open? (Shutter Speed)

The room will be bright if the shutters are open because light can enter. However, if you close the shutters, the space will become dark as the shutter speed determines how long the shutters remain open.

ISO Is Like A Curtain

The thickness of the semi-transparent curtain (ISO) also plays a role in determining how much light can enter the room. If you use a thick curtain, less light will enter the room. A thin curtain, on the other hand, will allow almost all of the morning to enter.

By understanding the distinctions among these elements, you can utilize them to gain authority over your photographs.

• Using long shutter speeds and wide apertures can be helpful when taking photos in the dark. However, increasing the ISO can result in grainy pictures.

• Using fast shutter speeds is an excellent way to capture motion.

To fully understand how ISO, shutter speed, and aperture work together, it's best to experiment with each setting. Only adjust other camera features once you feel comfortable with these. Check out this graphic for a clearer idea of how the three sets interact.

Detailed Explanation Of Exposure Triangle

How ISO, Aperture, And Shutter Speed Work

ISO (and ASA)

I mentioned ISO earlier. To clarify, ISO and ASA refer to the same thing.

• The abbreviation ISO stands for the International Organization for Standardization.

• On the other hand, ASA is an acronym for the American Standards Association.

Both terms refer to standardization and imply a meaning beyond mere light sensitivity. In photography, "ISO" and "film speed" refer to the light sensitivity of the camera's digital sensor or film that captures light.

Light sensitivity refers to the camera sensor or film's sensitivity to light. ISO is a number that indicates the minimum amount of light required for the sensor or film to capture well-exposed images. The sensor sensitivity scale follows a doubling pattern, where each subsequent number (such as 100, 200, 400, etc.) represents twice the sensitivity of the previous number.

Average ISO Range: 100 – 1600

Cameras usually have a minimum ISO of 100, meaning they are not very light-sensitive. There is no definite upper limit, though newer cameras tend to have higher maximum ISOs. However, shooting at extremely high ISOs is not recommended, and we will soon find out why.

Typically, capturing high-quality pictures on modern DSLR cameras using ISO 1600 is safe. If you shoot in low light, you have an exposure leeway of up to five stops.

Let's Take An Example To Explain How ISO Works

Suppose your camera's exposure meter mode indicates that at ISO 100, the camera can capture a photo with an aperture of f/11 and a shutter speed of 1/100 second. If the surrounding light decreases, and you want to maintain the identical shutter speed and aperture settings, increasing the ISO is the only option to obtain the same exposure. In this case, you can adjust the ISO number based on the amount of ambient light change.

If the amount of light decreases by one stop (halves), you need to adjust by setting ISO 200 to maintain the same level of exposure. ISO 200 is one stop higher than ISO 100, meaning it has the same effect as increasing the exposure by one stop.

Note: ISO Doesn't Alter The Exposure

There is a lot of confusion regarding ISO among photographers who claim that ISO changes exposure, but this is different.

The ISO standard covers the post-exposure process.

Signal amplification is a technique used in photography to increase the ISO number. However, higher ISO numbers can also amplify the noise in the image, similar to static in a signal amplification system.

Specks of white and black present across an image are called noise. They are more visible in the shadow areas. It should be noted that using a higher ISO is not free of drawbacks.

ISO FAQs

What Is Auto ISO?

Some cameras have Auto ISO Mode, which allows the camera to determine the best ISO setting for exposure.

How Does Auto ISO Work?

If there is too much light, the Auto ISO of your camera will not activate. When there is proper lighting, your camera will automatically use the lowest possible ISO setting. Suppose you choose the lowest ISO setting, either ISO 100 or ISO 200. The camera's Auto ISO feature will activate when the light gets increasingly faint. To maintain proper exposure, your camera will increase the ISO number.

Aperture And Aperture Blades

It can be explained simply as the camera lens opening to understand the aperture better.

The hole in the camera that allows light to enter and reach the digital sensor or film is known as the aperture. It is always represented as a fraction which denotes the ratio between the lens's focal length and the size of the aperture. Hence, the aperture cannot be described using an exact number.

Aperture = f/ or F-Stop

Also, the aperture varies based on the lens' focal length and the format of the lens in question. Gap is alternatively referred to as f-number or f-stop.

Aperture Experiment

Choose a lens with an aperture setting of f/2.8 or lower (like f/1.8 or f/1.4) to understand the physical concept of aperture. It's best if the lens also has a manual aperture ring with fractions and numbers engraved, such as f/16, f/11, f/8, f/1.8, and f/1.4, depending on the lens's aperture range.

To adjust the aperture, rotate the ring on the lens while monitoring the front of the lens. You'll see a small opening at the back of the lens that will grow or shrink as you turn the ring, depending on the direction in which you're rotating it.

This happens because the hole size in a camera lens is not fixed. There are small blades behind the lens that can move and change the size of the hole. You can observe this by comparing different lenses - the more aperture blades a lens has, the smoother the opening will be.

The amount of light a lens allows depends on the size of its opening. If your lens doesn't have a physical aperture ring, you can still try this exercise with your camera. You need to pay closer attention to how the lens opens and closes.

Aperture And Depth Of Field

Depth of field is a photographic term that is linked to aperture. In addition to regulating the light entering the camera, the aperture also determines how much a scene will be sharp and in focus.

 

• To put it, if the aperture (hole) is more significant, the area of the image in focus will be smaller. This means that an extensive aperture results in a shallow depth of field.

• A smaller aperture will increase the depth of field, which means that more of the frame will be in focus. In contrast, a larger aperture will decrease the depth of field.

Creative Applications Of Aperture

The fact that you can control the aperture, whether manually or otherwise, provides numerous opportunities for creative use. Controlling the depth of field is one of the creative ways to shoot, as you may already know.

When taking pictures of landscapes, cityscapes, seascapes, architecture, or group shots, you can achieve a more significant depth of field by stopping down the lens.

However, if you want the background (and foreground) to appear blurred and make your subjects like flowers, portraits, or newborns stand out, you need to use a large aperture and create a shallower depth of field.

There are lenses available that allow you to adjust the desired background blur effect. One such lens I can suggest is the Nikkor 135mm f/2 DC.

Bokeh

You will often hear the term "depth of field," which relates to photography's aperture. The language code for the output is EN-US, and the word was sourced from the Japanese dictionary. In photography, Bokeh refers explicitly to the quality of the blur in the background and not just the blur itself.

 

You can control the background blur in many ways, one of which is by adjusting the lens aperture.

Number Of Aperture Blades

Besides, other factors determine the quality of the out-of-focus effect, also known as Bokeh, such as the number of aperture blades on the lens.

 

A more significant number of objects in the background will result in a smoother bokeh. Additionally, the environment plays a role in determining the amount of blur.

The Background Matters

• Bokeh may not appear or be of poor quality if the background is solid or dark.

• On the other hand, if the scene contains many details and small patches of light, the quality of the Bokeh will significantly improve.

Shutter Speed

The second component of the exposure triangle is the shutter speed. The term "shutter speed" refers to when the camera's shutter remains open. The message implies that it estimates the duration the camera will be exposed to light in a particular scenario.

Indeed, you can control the length of time. The camera automatically controls the shutter speed in Auto mode and Aperture priority mode based on the aperture setting or the type of scene. Manually, the photographer must adjust the shutter speed.

The measurement of shutter speed is given in fractions of a second.

• The sequence of shutter speeds is 1/30, 1/60, 1/120, 1/250, and so on. Between 1/60 and 1/120 shutter speed, a speed increase of 1/60 of a second and a corresponding halving of light.

• If you increase the shutter speed to 1/30 instead, the shutter becomes slower. This results in twice the amount of light entering the camera.

Although it may seem confusing, we always refer to it as shutter speed, which can sometimes last for several seconds or even minutes. External tools can drag the shutter for any desired length of time. To capture long exposure shots, you'll need a remote trigger and your camera set to Bulb Mode to allow you to control the shutter speed manually.

Creative Applications – Freezing A Moment

Shutter speed can be used to stop motion. For example, a bird flying, a striker preparing to shoot the ball past the goalie, or a cyclist racing past onlookers at the Tour de France. This technique can be utilized in conjunction with a camera that has a rapidly fast shutter speed to record instances like a balloon popping, a bullet striking a wooden panel, or a glass window shattering at the precise moment of impact.

Typically, the mechanical shutter's limits make it difficult to capture high-speed action adequately. Recording fast-moving objects requires additional elements like a laser trigger and external lights. I'll explain more about these items later.

Shutter Speed And Motion Blur

Shutter speed can be used not only to freeze motion but also to capture motion blur. To achieve this, you need to keep the shutter curtain open longer - a technique known as dragging the shutter.

Using A Remote Trigger

I mentioned using an extended period for the shutter speed. This involves keeping the shutter open for several minutes or even hours. The camera's preset options do not include a shutter speed as long as I need it to be. To capture the image, switch to Bulb mode and press the shutter release button.

It can be challenging to take photos of things like star trails. Using an external shutter release trigger is recommended for the best results.

Exposure And The Exposure Triangle

To clarify, of the three elements (ISO, aperture, and shutter speed) that make up the exposure triangle, ISO is the only one that does not directly control the amount of light entering the camera. Instead, it affects how the image looks after capturing the exposure. However, it is still commonly referred to as part of the "ISO-aperture-shutter speed triangle."

The other two variables have an inverse relationship and are complementary. Before diving into this further, let's first clarify what exposure means.

Exposure

Exposure refers to the amount of light your camera captures, which is determined by the combination of shutter speed and aperture.

The resulting image is determined by the aperture and shutter speed settings on your camera, whether you manually set them or the camera automatically sets them.

Exposure refers to the brightness level of your images. If an idea is too bright, it is over-exposed. If an image is too dark, it is under-exposed.

Sometimes, we purposely need the brightness of the exposure to be high, while other times, we require it to be low. The decision is entirely up to the photographer and is based on their preference. It is generally best to correctly expose not too bright or dark pictures.

The Relationship Between Aperture and Shutter Speed

As I stated previously, an inverse relationship exists between aperture and shutter speed. This means that the size of the aperture and the length of time the shutter is open affect the amount of light captured.

In theory, it is possible to adjust either of the two aspects to achieve a balanced exposure.

However, the type of scene you want to capture can limit you in practical situations.

• When capturing landscapes, use a smaller aperture that requires properly adjusting the shutter speed to expose the photograph.

• In contrast, when taking portraits, it is common to use a wider aperture which requires a faster shutter speed to expose the photo properly.

You cannot simultaneously open up the aperture, drag the shutter, or perform the opposite with both settings. If you increase the size of the aperture, you will need to increase the speed of the shutter to balance the amount of light. Conversely, if you decrease the speed of the shutter, you will need to decrease the size of the aperture to ensure that the camera can handle the reduced amount of light.

To Recap The Aperture Priority & Shutter Speed Priority Modes:

• In aperture priority mode, the camera will automatically adjust the shutter speed to regulate the amount of light entering the lens.

• When using shutter speed priority mode, the camera will automatically adjust the aperture for you. If you keep the ISO the same, the shutter speed and aperture settings will remain unchanged.

Let's Do Some Basic Exposure Triangle Workout!

Aperture Priority Mode

• Take some photos using a low aperture setting, which means a bigger aperture opening and more light. You can use settings like f/1.4 or f/2.8, which are great for portraits, indoor shots, and night scenes.

• Take some photos using a high aperture value, such as f/22. This is best for landscape photography and will result in the image's broader depth of field and sharpness.

Shutter Speed Priority

• To capture a still moment, use a fast shutter speed such as 1/1000 second.

• To capture sufficient light during the nighttime, it might be necessary to use a longer shutter speed of one or two seconds.

Change The ISO

• Try changing the ISO setting to 6,400 to observe the impact on your image.

• To see the difference, take a photo with a low ISO setting, such as 50.

Wrapping Up........

In today's era of innovation, it is essential to be familiar with and adapt to technology to succeed in the future, especially if you are pursuing a photography career. One option that may help you pursue your photography goals is learning about proper exposure techniques. This blog has explained various terms, procedures, and queries related to photography exposure. We hope the information will help you find what you want regarding photography exposure.

Frequently Asked Questions (FAQs)

Below are frequently asked questions about the Exposure Triangle, which consists of ISO, shutter speed, and aperture.

Q. What Is Exposure, And How Is It Used?

Ans. Exposure is a crucial term in photography. When you click a picture, you open the camera's aperture by pressing the shutter button, allowing the light to enter and trigger the sensor. Exposure refers to the quantity of light that enters the camera's sensor and creates images over time.

Q. What Are The 3 Components Of Exposure?

Ans. The exposure triangle comprises shutter speed, aperture, and ISO. One way of understanding this is to compare it to filling a bucket with water. In this analogy, the camera sensor is the bucket, and the light is the water.

Q. What Is An Example Of An Exposure Triangle?

Ans. Simply put, the exposure triangle concept decides whether the motion will look blurry or still in a photo. For instance, the values for this concept are 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8, 1/4, 1/2, etc. Additionally, most cameras have a maximum limit of 30 seconds for the shutter to remain open.

Q. What Is The Formula For Exposure?

Ans. The relationship between the scene, camera, and captured image in photography is governed by the equation: Image brightness is proportional to the scene illumination, subject reflectivity, lens aperture area, open shutter time, and ISO sensitivity.