In this photography series, we've covered the fundamentals of light, the Camera Obscura, image formation, shutter speed, aperture, and ISO. Now, it's time to bring these elements together to form the exposure triangle, the foundation of achieving perfect exposure in your photographs. By understanding the exposure triangle, you will be equipped to capture stunning images in a wide range of conditions and creative scenarios.

The Three Pillars of the Exposure Triangle.

The exposure triangle consists of three interconnected elements: shutter speed, aperture, and ISO. Each element plays a crucial role in determining the final exposure of an image:

  1. Shutter Speed: Controls the duration of light entering the camera by adjusting the time the shutter remains open.
  2. Aperture: Regulates the amount of light entering the camera by adjusting the size of the lens opening.
  3. ISO: Alters the camera sensor's sensitivity to light, allowing for proper exposure in various lighting conditions.
The exposure triangle, showing the relationship between apertureshutter speed, and ISO. Image by WClarke and Samsara

Balancing the Exposure Triangle.

Achieving perfect exposure requires a delicate balance between the three elements of the exposure triangle. Adjusting one element will necessitate compensating changes in the other two to maintain proper exposure. The key to mastering the exposure triangle is understanding how each element affects the final image and making informed decisions based on the desired creative effects:

  1. Shutter Speed: Faster shutter speeds “freeze” motion, while slower speeds convey a sense of motion or blur.
  2. Aperture: Larger apertures create a shallower depth of field, while smaller apertures produce a greater depth of field.
  3. ISO: Higher ISO values increase the sensor's sensitivity to light, but may result in increased noise, while lower values reduce noise but require more light for proper exposure.

Finding the Right Balance for Your Vision.

Mastering the exposure triangle is a process of experimentation and experience. By understanding the interplay between shutter speed, aperture, and ISO, you can make informed decisions to achieve the desired exposure and creative effects in your photographs.

  1. Determine your priorities: Decide which element(s) are most critical to your creative vision (e.g., motion control, depth of field, or image quality).
  2. Adjust the settings: Make initial adjustments to the exposure triangle elements based on your priorities.
  3. Review and refine: Review the captured image and make further adjustments as necessary to achieve the perfect exposure.

There are some typical starting rules, as an example if it is sunny there is a rule known as the “Sunny f/16 rule”, this rule suggests to set your aperture to f/16, your ISO to say 100, and then yiour shutter speed should be the reciprical of the closest value, for example if your ISO is 100, your shutter speed would be 1/100, if it was 200 it would be 1/200.


The exposure triangle is the cornerstone of achieving perfect exposure in photography. By mastering the interplay between shutter speed, aperture, and ISO, you will be well-equipped to capture stunning images that align with your creative vision. With the knowledge gained throughout this series, you are now ready to explore the world of photography with confidence and skill.

a photo of a clouds formation in the sky
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