Photography Fundamentals: Aperture, Shutter Speed, and ISO

A reference guide to the fundamentals of photography such as: Shutter Speed, Aperture and ISO.

Photography involves the art of directing light and manipulating shadow. The core of this creative process lies in the principle of exposure. Exposure, which refers to the amount of light that enters your camera, is influenced by three key factors; aperture, shutter speed and ISO. These elements work together in harmony to achieve a balanced and properly exposed photograph. In this blog post, we will explore “The Trinity of Exposure” and examine how these settings affect the images you took.

1. Aperture

An infographic of aperture to illustrate various settings.
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A camera’s aperture is a mechanical term that refers to the size of the opening at the back of the lens. This opening affects the amount of light that is let into the camera and is captured by the sensor.

Your camera’s aperture, which is sometimes referred to as the F-stop, is one of the most essential aspects of your photograph’s exposure, but it also impacts the “depth of field,” which refers to how much of the image is in focus. This is a significant stylistic decision that will affect the overall look and mood of your image.

How does it affect your photos?

  • Depth of Field; Aperture determines how focused your image is displayed. A wider aperture (f stop), such as f/1.4, creates a depth of field by blurring the background and focusing on the subject. A narrower aperture (f stop) produces a wide depth of field in which everything remains widely in focus.
  • Light Intake; An aperture enables light to enter, which is useful in low-light situations or when generating a beautiful background blur, commonly known as bokeh. On the other hand, a narrower aperture reduces the amount of light which can be beneficial when shooting in daylight.
  • Creative Control; By adjusting the aperture you have the power to create effects control the background elements and influence the mood of your photographs.

2. Shutter Speed

An infographic of shutter speed in multiple settings.
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The shutter speed of a camera is the amount of time the shutter is open, exposing light to the camera sensor. It’s basically how long your camera takes to take a photo. This has a few significant effects on how your photographs will appear.

When you apply a longer shutter speed (sometimes referred to as a “slow” shutter speed), you expose your sensor for an extended period of time. The first significant result is motion blur in which the moving subjects in your photograph will appear blurred. This technique is frequently used in vehicle and motorcycle commercials to provide a sense of speed and velocity.

The Impact on Your Photos:

  •  Capturing Motion; Faster shutter speeds like 1/1000s freeze moving subjects in detail while slower speeds like 1/30s capture motion with a deliberate blur.
  •  Exposure Control; Shutter speed works hand in hand with aperture. Longer shutter speeds let in light while shorter shutter speeds restrict light intake.
  •  Creative Possibilities; Experimenting with exposures can result in mesmerizing effects such as captivating light trails, starbursts and silky waterfalls.

3. ISO

An infographic of ISO in multiple settings.
Image source:

The ISO setting of a camera determines the sensitivity of the film or digital sensor to light. A lower ISO value refers to a lower level of light sensitivity, and a higher ISO value correlates to an increased level of light sensitivity. ISO is a fundamental component of the triangle exposure in photography, — along with aperture and shutter speed — and plays an essential role in the quality of your photos.

Selecting the right ISO:

  • ISO 100: is considered the optimal selection for capturing images in outdoor environments during sunny days.
  • ISO 400: in situations where the lighting condition is less intense, such as being indoors near a window or outdoors on a cloudy day, it is ideal to use a slightly higher ISO setting.
  • ISO 800: You’ll be working in this ISO setting whenever you take photos indoors without the assistance of an additional light source such as a flash.
  • ISO 1600 or higher: You’ll need a high ISO for shooting in low-light conditions, such as at night or indoors. If movement is involved, you’ll want to pair that high ISO with a rapid shutter speed, as well.

Finally, it’s crucial to understand the concept of the “Trinity of Exposure” in photography. These three elements include Aperture, Shutter Speed and ISO – which collectively provide you with the power to control your images. As you progress on your practice, don’t hesitate to experiment with combinations of these settings. Share your stories and experiences in the comment section below!

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