Estimated reading time: 9 minutes

Mastering the exposure triangle is the single most important step for any landscape photographer moving beyond Auto mode.

Digital photography may seem like a total replacement for film. However, in reality, it’s essentially a high-tech love letter to its chemical ancestor. Understanding concepts like exposure triangle photography reveals the pervasive influence of film. It’s evident from the way cameras feel in your hand to the math behind the sensor. In fact, mastering exposure triangle photography can help bridge your knowledge between traditional and digital techniques.

Here is how the “old school” continues to shape the “new school.” It does so in the art of applying the exposure triangle to photography.

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When I started photography, 40 years ago now, the question of the exposure triangle didn’t arise! I had a very basic camera, and the only choice available to me was to compose and press the shutter.

Very quickly, my first reflex opened up new perspectives. This led to new questions. What do we do with these three adjustment options? The Pentax P30 that I had allowed me to adjust the aperture. I could also adjust the speed. Of course, I was able to choose the sensitivity of the film.

With each image, I understood the impact of choosing different speeds and apertures. This choice greatly affected the final result. I quickly gravitated towards landscape photography, often choosing small apertures and slow speeds.

Unfortunately, I lost my many slides from that time, including those from a trip to Quebec and stays in Scotland.

I am much more careful with my digital files, so my backup system is much more solid now. I will tell you about it soon.

The Language of the Sensor

The very foundations of digital imaging are borrowed directly from the physical properties of 35mm film. Exposure triangle photography relies on the same principles for capturing images, whether on film or a digital sensor.

• Full-Frame Standards match the standard of a single frame of 135 film. Leica established this standard in the 1920s.
• ISO Ratings: In the film days, ASA/ISO referred to how sensitive the silver halide crystals were to light. Digital cameras kept this scale so photographers wouldn’t have to relearn how to expose an image.
• Crop Factors: Lenses are still measured by focal lengths (like 50mm) based on how they behaved on film. If a sensor is smaller than a film frame, we use a “crop factor” to describe the difference.

You have surely encountered these three terms if you have ever exited the “Auto” mode of your camera. They are Aperture, Shutter Speed, and ISO. Together, they make up the Exposure Triangle. With exposure triangle photography, you take control of these settings for creative results.

Consider these three elements as the pillars that support the brightness of your image. If you modify one, you generally need to adjust the others to maintain balance. For anyone starting out, understanding how the exposure triangle works in photography brings clarity to your creative process.

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Effect of Aperture (The Diaphragm) on the Exposure Triangle

The aperture corresponds to the size of the opening in the lens that lets in light. It is measured in f/number (e.g., f/1.8, f/8, f/22). In photography, setting the aperture is one part of controlling the exposure triangle effectively.

• The smaller the number (f/1.8): The aperture is large. A lot of light enters. It’s ideal for background blur (bokeh).
• The larger the number (f/22): The aperture is small. Little light enters. Everything is sharp, from the foreground to the horizon.

The quality of a lens mainly lies in its brightness and therefore in its maximum aperture. A classic series “opens” at f/4, while bright lenses allow for an aperture of 2.8. For my part, the lenses on my two Canon cameras open at f/4, my Leica opens at f/1.8, and the one mounted on my Nikon FM has a maximum aperture of f/1.4.

Effect of Shutter Speed (Time) on the Exposure Triangle

It is the duration for which the sensor is exposed to light. It is expressed in fractions of a second (e.g., 1/1000s, 1/30s), which is also a key factor in the exposure triangle for photography.

• Fast shutter speed (1/1000s): “Freezes” motion. Essential for sports or birds in flight.
• Slow speed (1/10s or several seconds): Creates artistic blur or allows capturing stars at night. Be careful, a tripod is often necessary! In this example, a low speed makes the bus like a ghost.

Effect of ISO (Sensitivity) on the Exposure Triangle

ISO represents the sensitivity of the sensor to light. In exposure triangle photography, adjusting ISO gives you flexibility in challenging lighting conditions.

• Low ISO (100 – 200): Ideal in full sunlight. The image is pure and sharp.
• High ISO (3200 – 6400): Allows you to photograph in low light. Be careful of “digital noise”. Those little grains can spoil the image quality.

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How to balance the triangle?

This is where the magic (and frustration) begins. Exposure is a matter of compromise. Moreover, exposure triangle photography requires balancing these three elements for the best image quality.

The golden rule: If you close your aperture by two stops, you reduce the light. You must slow down your shutter speed or increase your ISO. This compensates and maintains the same brightness.

Action	Effect on light	Creative consequence
Opening diaphragm	Increase	No more blur
Level up speed	Decrease	Fix the movement
Level up ISO	Increase	Higher grain

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What to do if you’re a landscape photographer?

While we have seen how important composition is, let’s explore how to make the most of light.

In landscape photography, we generally aim for maximum depth of field. Our subject should be sharp across all planes. To achieve this, we use the smallest aperture possible, knowing that closing the aperture too much can introduce artifacts. That’s why, although lenses can stop down to f/22, we typically work at f/8 or f/11.

We already discussed the f/64 group in a previous issue. These photographers worked with large-format cameras. This allowed them to close the shutter to apertures that our modern lenses cannot achieve.

Sometimes, we seek particular effects. We will use a wide aperture to leave part of the scene in an artistic blur. An example is this image taken on the Scottish moor. It hints at the Isle of Lewis.

If you want to increase the exposure time in bright light, you need to use filters to limit the exposure. This is the technique used for this long-exposure image. A 10 ND filter allowed for a longer exposure time, giving the ocean its milky appearance. For this picture, the exposure time was 12 seconds!

In summary

Learning the exposure triangle means transitioning from being a spectator to becoming a creator. You choose whether you want a portrait with a blurred background. Alternatively, you can have a waterfall with a silky water effect. Ultimately, exposure triangle photography empowers you to achieve your creative vision with every shot.

Explore how these principles shape my own coastal work in the portfolio →