With the rising popularity of photography spreading across the populace, you are sure to come across the word exposure mentioned everywhere. “Exposure” is a carry forward from the days of film photography, where the film needed to be physically exposed inorder to capture an image. The principle has stayed true even into the current world of digital photography - where the image sensor must be exposed to light to register an image. And so have the principles of what settings comprise an exposure!

What really is Exposure?

Exposure in photography simply refers to the allowed amount of light that enters the camera and registers on the image sensor. The amount of light that is allowed to register on the camera’s image sensor is controlled at 3 distinct points (in order) - the aperture, the shutter and the ISO, which collectively deliver a single exposure, or in other words, produce a single photo. 

As mentioned, an exposure is a single shutter cycle, producing a single image in normal shooting scenarios. There are two distinct terms for capturing images in different lighting conditions you should be aware of - one is called a long exposure that refers to a single long shutter cycle to gather enough dim light. The other is called a multiple exposure, which involves a series of shutter cycles, effectively layering a series of photographs in one image.

The 3 camera settings that control the exposure - the Shutter Speed, the Aperture and the ISO are collectively referred to as the Exposure Triangle. Allow me to elaborate on these settings in the context of generating exposures:

1. Aperture: The Gateway to Creativity ⭕

Aperture behaves exactly like the pupils in our eyes - adjusting the opening which dictates how much light is allowed to enter the eye, and in this case, a series of blades in the lens that control a circular opening to perform the same function. Aperture is measured in f-stops, such as f/1.8, f/5.6, or f/16. A lower f-stop (e.g., f/1.8) means a wider aperture, allowing more light to hit the sensor, while a higher f-stop (e.g., f/16) means a narrower aperture, letting in less light.

Controlling the aperture opens the exciting avenue of creativity as it pertains to controlling the DOF (Depth of Field). A wide aperture (low f-stop like f/1.8) creates a shallow depth of field, resulting in a blurred background, known as bokeh. This is perfect for portraits, where the subject pops against a dreamy backdrop. On the other hand, a narrow aperture (high f-stop like f/16) extends the depth of field, making everything from the foreground to the background sharp and clear, ideal for landscape photography.

2. Shutter Speed: Capturing Motion/Stillness 📸

Shutter speed, expressed in seconds or fractions of a second (e.g., 1/1000s, 1s), determines how long the camera's sensor is exposed to light. The shutter mechanism consists of a series of plastic blades that block light from falling on the sensor. When the shutter button is pressed, they move up-down at a speed set by the photographer, allowing light to fall on the sensor for that duration. Fast shutter speeds (like 1/1000s) freeze fast-moving subjects in photos, while slow shutter speeds (like 1s) allow motion blur of the subject or even the whole frame.

The choice of shutter speed evidently impacts exposure. The name of the game with shutter speed is to know your subject, set the speed and control exposure with aperture and ISO. A fast shutter speed limits the amount of light entering the camera, often requiring a wider aperture or higher ISO setting to achieve a well-exposed image. Conversely, slow shutter speeds demand less light, often necessitating a narrower aperture or lower ISO setting. 

3. ISO: Sensitivity to Light 🕯️

ISO setting is a numerical representation of your camera sensor’s sensitivity to light. A low ISO setting (ISO 50/100) denotes a lesser sensitivity to light and in bright scenarios,  produces crisp and noise-free images. On the other hand, a high ISO setting (ISO 3200/6400) denotes a higher sensitivity to light, making it suitable for low-light conditions. However, owing to the working principle of the ISO function, a high ISO setting results in noise, which negatively impacts image quality.

Understanding ISO is essential as it allows you to adapt to various lighting scenarios. For instance, in bright sunlight, a low ISO setting allows you to maintain image quality while using a narrow aperture and fast shutter speed. In dimly lit environments, a higher ISO setting lets you capture images with a wider aperture and faster shutter speed without sacrificing exposure - with noise being introduced into the photo as well. 

Nothing in life is ever free, and it helps to think of noise as the cost of being able to shoot in very dimly lit scenarios. Which is why as the professional you are becoming, always remember to add light to your scenes to ensure you keep the ISO low and capture a sharper noise-free image, unless the frame you aim to capture requires the natural dim lighting (such as the night sky). Also, if you must shoot in dim lighting and still want a crisp image, consider using a tripod (requires subjects that will be relatively still though!).  

Balancing the Exposure Triangle 🔺

With your understanding of the 3 aspects of the exposure triangle now strong, your next natural progression is to master exposure control and find the perfect harmony between aperture, shutter speed, and ISO for each photo you capture. Here are some examples to cement the concepts of exposure control like second nature:

• Scenario 1: Portrait Photography

• To achieve a beautiful bokeh effect, choose a wide aperture (e.g., f/1.8).

• Balance the exposure by selecting a faster shutter speed (e.g., 1/200s) to prevent overexposure.

• Adjust ISO as needed to maintain image quality.

• Scenario 2: Landscape Photography

• Opt for a narrow aperture (e.g., f/16) to ensure everything is in sharp focus.

• Counteract the reduced light with a slower shutter speed (e.g., 1/30s) or a higher ISO if necessary.

• Scenario 3: Action Sports Photography

• Use a fast shutter speed (e.g., 1/1000s) to freeze fast-moving subjects.

• Compensate for the reduced light with a wider aperture and higher ISO.

Creative Expression through Exposure 🫵

Exposure control not only allows you to capture images perfectly, but as is the nature with photography, allows you to deliberately choose settings (that can be counterintuitive to capturing perfectly exposed photos) to instead capture photos that display your artistic perspective of the world around you. Here are some examples of how you can play with exposure settings:

• Silhouettes: By intentionally underexposing a subject against a bright background, you can create dramatic silhouettes that evoke mystery and intrigue.

• Long Exposure: Using slow shutter speeds, you can capture light trails from moving vehicles, stars streaking across the night sky, or the gentle flow of waterfalls. This technique adds a sense of motion and time to your images.

• High Key and Low Key: High-key photography involves intentionally overexposing an image to create a bright, ethereal look, while low-key photography uses underexposure to create moody, dramatic effects.

• HDR (High Dynamic Range): This technique involves blending multiple exposures of the same scene to capture both shadow and highlight details, resulting in vivid, balanced images.

• Night Photography: Experimenting with exposure during nighttime, especially with the help of a tripod, can yield stunning results, from capturing the brilliance of city lights to the mystique of starry skies.

The Beauty of Trial and Error 👍

Exposure is a careful balance between the aperture, the shutter speed and the ISO settings when capturing the perfectly exposed photo. But by the same hand, exposure is also your avenue to play around the aperture, shutter speed and the ISO to capture creatively captivating photos. Attaining complete mastery in exposure control requires a ton of practice, as with any other avenue in life. However, photography is an art form at its core, and there is no one rigid way of shooting images. Becoming a professional camera wielder is possible only when you fear not the process of trial and error, practice regularly and find your exposure style to lean into.

In summary 🥂

One of my favorite quotes from the world of photography is:

“Exposure control is an art within the art of photography.” 

Whether aiming for a perfectly exposed photo or an avenue of artistic expression, exposure control is your primary weapon of choice for capturing 90% of your vision (the last 10% is what you use an editing software for!). Exposure control is what allows you to harness the full potential of your camera’s image sensor, whilst ensuring that you never miss a shot because you fumbled with your setting. And finally, having a firm grasp on exposure control brings you one step closer to not only looking like a professional, but also becoming a professional shooter.