Aperture vs. Shutter Speed vs. ISO: The Exposure Triangle Explained
Photography is a delicate dance between light and settings, and understanding the exposure triangle is the key to mastering this art. The exposure triangle refers to the relationship between three fundamental camera settings: aperture, shutter speed, and ISO. Together, they determine how much light hits the camera sensor and how your final image looks.
In this guide, we'll explore the concepts of aperture, shutter speed, and ISO, how they work together, and when to adjust each one. Whether you're using a Canon DSLR or a mirrorless camera, this breakdown will help you capture better images in every lighting condition. As always, we’ll demonstrate how we apply these techniques at G10 Studio during our professional photography sessions in Aruba.
What is Aperture?
The aperture controls the size of the lens opening and affects how much light enters your camera. It is measured in f-stop numbers such as f/1.8, f/4, or f/16.
The aperture plays a crucial role not only in exposure but also in depth of field. A wider aperture (represented by a lower f-stop number) lets in more light and creates a shallow depth of field, which is ideal for portraits where you want the subject in focus and the background blurred. On the other hand, a narrow aperture (higher f-stop number) allows less light to enter but increases the depth of the field, making it ideal for landscapes where you want everything in the frame to appear sharp.
Understanding how to adjust your aperture in relation to lighting and the desired visual effect is fundamental to good photography.
Want a full breakdown? Read our blog: What is aperture?
What is Shutter Speed?
Shutter speed determines how long your camera sensor is exposed to light. It directly affects how motion appears in your photos.
A fast shutter speed (like 1/1000s) freezes motion, capturing sharp images of moving subjects such as athletes or wildlife. This is essential when you want to avoid blur from movement. A slow shutter speed (like 1/30s or slower) allows more light in and is used creatively to introduce motion blur, such as in waterfall or night sky photography.
However, using a slower shutter speed can introduce a camera shake, so a tripod is often necessary. Balancing shutter speed with aperture and ISO ensures your image remains sharp and well-exposed.
What is ISO?
ISO is the camera sensor's sensitivity to light. It allows you to brighten or darken your image without changing the aperture or shutter speed.
A low ISO (e.g., ISO 100) is ideal for brightly lit situations and produces the cleanest images with the least amount of noise. A high ISO (e.g., ISO 3200 or more) is useful in low-light settings but can introduce digital noise or grain into your image.
Modern cameras have improved high ISO performance, especially brands like Canon. Still, for the best image quality, it is ideal to keep ISO as low as possible and rely on aperture and shutter speed adjustments first.
Want to master low-light photography and image quality? Learn what ISO is in photography and why it matters.
How Aperture, Shutter Speed, and ISO Work Together
Together, these three elements form the exposure triangle, and understanding their interaction is critical. Adjusting one setting usually requires adjusting one or both of the others to maintain proper exposure.
Here’s how each affects the other:
If you widen your aperture to allow more light, you might need a faster shutter speed to avoid overexposing the image.
If you use a slower shutter speed for creative blur, you may need to narrow the aperture or reduce ISO to maintain balance.
In low-light conditions, you may have to increase ISO while using a wide aperture and slower shutter speed to achieve a usable exposure.
Example: Shooting a Beach Portrait
Imagine you're photographing a subject at Aruba’s Eagle Beach during the golden hour:
Aperture: f/2.8 for a blurred background and subject isolation.
Shutter Speed: 1/800s to compensate for the wide aperture and prevent overexposure.
ISO: 100 to keep the image crisp in bright light.
Each setting complements the others. A change in one requires adjustments in the rest to maintain consistent exposure.
Choosing the Right Setting Based on Scenario
Different photography situations require different exposure settings. Below are several use cases with ideal configurations:
Portrait Photography
Aperture: Wide (f/1.8 to f/2.8) for background blur.
Shutter Speed: 1/125s or faster to avoid motion blur.
ISO: 100–400, depending on light availability.
Landscape Photography
Aperture: Narrow (f/8 to f/16) for deep focus.
Shutter Speed: Slower (use a tripod).
ISO: 100 for best clarity.
Sports and Action
Aperture: Mid-range (f/4) for subject clarity.
Shutter Speed: Fast (1/1000s or more).
ISO: 400–800, depending on lighting.
Refer to an ISO, aperture, shutter speed chart or download an aperture, shutter speed ISO chart PDF to keep handy while shooting.
Aperture vs Shutter Speed vs ISO: Key Differences
Let’s break down the fundamental differences:
Aperture: Controls the amount of light entering and determines how blurry or sharp the background appears.
Shutter Speed: Determines how movement is captured, ranging from freeze frame to motion blur.
ISO: Adjusts the camera sensor’s sensitivity to brightness.
Understanding these roles enables you to make informed decisions that align with your photography style.
Best ISO, Aperture, and Shutter Speed Settings by Condition
Here is a quick reference chart for various shooting conditions:
Daylight Portraits
Aperture: f/1.8 – f/2.8
Shutter Speed: 1/250s
ISO Range: 100–200
Landscape (Day)
Aperture: f/8 – f/16
Shutter Speed: 1/60s – 1/125s
ISO Range: 100
Sports / Action
Aperture: f/2.8 – f/4
Shutter Speed: 1/1000s or faster
ISO Range: 400–800
Night Photography
Aperture: f/2.8 – f/4
Shutter Speed: 1s – 30s
ISO Range: 800–3200
This chart provides a helpful starting point, but remember that lighting and creative goals may require on-the-spot adjustments.
Real-World Applications at G10 Studio
At G10 Studio, we use the exposure triangle intuitively across all sessions. During our photography in Aruba, conditions can change quickly due to sunlight, reflections from the water, and shifting cloud cover.
In bright daylight, we may shoot wide open at f/2.0 for beautiful portraits and use a fast shutter speed like 1/1000s with ISO 100. At night, for romantic evening shots near the shoreline, we use a smaller aperture and longer shutter speeds and bump the ISO to 800 or more—always balancing the triangle.
Each shoot is a lesson in lighting, and knowing how to use the triangle allows us to make quick, smart decisions to create stunning results.
Common Aperture Mistakes to Avoid
Many beginners tend to overlook how aperture impacts more than just exposure. Mistakes like always using the widest aperture, forgetting about depth of field in group shots, or not adjusting shutter speed accordingly can lead to poor image quality.
To learn more, check out 5 Common Aperture Mistakes.
Conclusion
Understanding the balance between aperture vs shutter speed and ISO is crucial for creating well-exposed, creative images. Each setting affects your photo in a unique way, but together, they give you the freedom to shoot in any condition and style.
With practice, managing the exposure triangle becomes second nature. Whether you're shooting portraits at sunrise or long exposures at night, knowing how to adjust these settings gives you complete creative control.
At G10 Studio, we rely on this balance every day during our professional photography in Aruba. With a little practice and experimentation, you can too.
Looking to perfect your exposure triangle skills? Reach out today and schedule a custom shoot or photography lesson with our expert team.
