Understanding the Exposure Triangle: ISO, Shutter Speed, and Aperture

If you're new to photography or just starting to explore manual mode, you've probably heard the term "Exposure Triangle." It sounds complicated at first, but understanding how ISO, Shutter Speed, and Aperture work together is key to mastering your camera and taking control of your shots. In this post, we’ll break down each of the three elements of the Exposure Triangle and explain how they interact to help you capture the perfect image.

What is the Exposure Triangle?

At the heart of photography lies a delicate balance between three crucial settings: ISO, Shutter Speed, and Aperture. These settings control how much light enters the camera, and each one has a specific role in shaping the final image. When combined, they ensure your photo is neither too bright nor too dark, and that it captures the essence of what you're trying to shoot.

ISO: Sensitivity to Light

ISO is the setting that determines how sensitive your camera’s sensor is to light. In simple terms, the higher the ISO number, the more sensitive your camera is to light, which allows you to shoot in lower light conditions. However, there’s a catch: increasing ISO can also introduce noise or grain into your images, which can make them look less sharp or clear.

How ISO Affects Your Image:

Low ISO (100-400): Best for bright, well-lit conditions. It produces the cleanest images with the least noise.

Medium ISO (400-800): Useful in moderate lighting conditions like indoor settings.

High ISO (1600 and above): Essential for low-light situations or when shooting at night, but expect more grainy textures.

Tips:

Keep ISO as low as possible for the clearest images.

Use a higher ISO when shooting in dim light, but be mindful of introducing noise.

Shutter Speed: How Fast Your Camera Takes the Shot.

Shutter speed refers to the amount of time the camera’s sensor is exposed to light. The faster the shutter speed, the less time light has to hit the sensor. This affects how sharp or blurry motion appears in your photos. Faster shutter speeds freeze motion, while slower speeds allow motion to blur, creating a sense of movement.

How Shutter Speed Affects Your Image:

Fast Shutter Speed (1/500s, 1/1000s): Freezes fast-moving subjects like athletes, wildlife, or moving vehicles. I often photograph sessions at the beach, where wind is blowing hair all around - I use a fast shutter speed to "freeze" the motion, so the client's hair doesn't look blurry. .

Slow Shutter Speed (1/30s, 1/60s): Captures motion, like the blur of water in a waterfall or light trails from cars. In recent years, a popular shot at weddings is where the bride and groom are in focus and their whole bridal party around them is blurry - that is shot by keeping the bride and groom still, and asking everyone around them to walk quickly. Since the bride and groom are still, the slower shutter speed keeps them in focus, but blurs the fast-.moving bridal party because the shutter did not have time to close before movement happened.

Tips:

Use a fast shutter speed to avoid motion blur if you're shooting something in motion.

Use a tripod for long exposure shots to prevent camera shake from slow shutter speeds.

Aperture: The Size of the Lens Opening

Aperture controls the size of the opening in your lens that lets light through to the sensor. It’s measured in f-stops (e.g., f/1.4, f/8, f/16). A wide aperture (e.g., f/1.4) means a large opening that lets in a lot of light and creates a shallow depth of field, while a narrow aperture (e.g., f/16) means a smaller opening that lets in less light but increases the depth of field, keeping more of the scene in focus.

How Aperture Affects Your Image:

Wide Aperture (f/1.4 to f/5.6): Ideal for portraits where you want a blurred background (bokeh) and a sharp subject.

Narrow Aperture (f/8 to f/22): Best for landscape photography, where you want everything from the foreground to the background in sharp focus.

Tips:

Use a wide aperture for a beautiful blurred background in portraits.

Use a narrow aperture to get a sharp, clear focus in landscape photos.

How the Exposure Triangle Works Together

Now, the real magic happens when you adjust these three settings together. Here’s how they balance each other out:

ISO and Shutter Speed:

If you increase your ISO to capture more light, you can afford a faster shutter speed, which helps freeze motion.

If you decrease ISO to avoid noise, you may need to lower your shutter speed, which might result in motion blur unless you stabilize your camera or use a tripod.

Shutter Speed and Aperture:

A faster shutter speed requires more light, so you might need to open the aperture wider (lower f-number) to compensate.

If you want a narrow aperture for more depth of field, you may need to slow down the shutter speed to let in enough light.

ISO and Aperture:

A wider aperture lets in more light, so you can use a lower ISO for a cleaner image.

If you need a narrow aperture for more focus, you might need to increase the ISO to make up for the reduced light.

The Key Takeaway: Exposure Is a Balancing Act

The trick to getting perfect exposure lies in understanding how these three elements work together and adjusting them based on your scene and goals. It’s all about finding the right balance between the amount of light needed, the speed at which the camera captures the scene, and the depth of field you want to achieve.

A Simple Formula to Remember:

Too Bright: Lower the ISO, use a faster shutter speed, or use a narrower aperture.

Too Dark: Increase the ISO, use a slower shutter speed, or use a wider aperture.

By experimenting with these settings, you’ll quickly learn how to control the exposure triangle to suit your creative vision. So, the next time you pick up your camera, take a moment to adjust these settings, and don’t be afraid to play around with different combinations to achieve your desired results!

Conclusion: Practice Makes Perfect

The Exposure Triangle is the foundation of manual photography, and mastering it is a journey. Whether you’re shooting weddings, portraits, landscapes, or action shots, understanding ISO, Shutter Speed, and Aperture allows you to create images exactly how you envision them. So, grab your camera, start experimenting with these settings, and soon enough, you’ll be confidently controlling your exposure, one shot at a time. Let me know if you found this post helpful!

Now, here are some examples of a small aperture (big f/number) -

You will notice much more of the foreground and background are in focus.

Here are some examples of a slow shutter speed:

You will notice the movement is captured, making the water look "soft" while the unmoving pier stays in focus, and the ferris wheel looks like it's spinning, while the buildings and light poles remain in focus.

Here are some examples of a fast shutter speed.

Here you can see the details of the waves, despite their constant motion.