Learning to See the Light
Every great photograph begins with one decision: how much light reaches the sensor. It sounds simple, but that single question unfolds into one of the most nuanced and creative conversations in all of photography. My name is Michael, and through the Frame by Frame education series, I want to walk you through the foundational concepts I wish someone had laid out clearly for me when I was first starting out.
We are going to begin with the exposure triangle, the three camera settings that, together, determine how bright or dark your image is, how motion is rendered, and how much of the scene is in sharp focus. Once you understand how these three elements interact, you will have real creative control over your images rather than just pointing and hoping.
What is Exposure?
Exposure is the total amount of light that reaches your camera's sensor when you take a photograph. Too little light and the image is underexposed, dark, muddy, and lacking detail in the shadows. Too much light, and it is overexposed and washed out, with highlights that have lost all texture and detail. A well-exposed image captures the scene with the range of light and shadow that feels true to what you saw.
Achieving the right exposure is not a single dial or button; it is the result of three separate settings working in balance. Those three settings are your aperture, your shutter speed, and your ISO. Change any one of them, and the others may need to compensate to maintain the same overall brightness. That relationship is the exposure triangle.
Aperture
Aperture refers to the opening inside your lens through which light passes. It is measured in f-stops, numbers like f/1.8, f/4, f/8, and f/16. Here is the part that trips up almost every beginner: the smaller the f-stop number, the wider the opening.
A wide aperture (like f/1.8) lets in a large amount of light and produces a shallow depth of field, meaning only a narrow plane of the image is in sharp focus, while the background blurs into soft, creamy out-of-focus tones. This is the look you see in portraits where the subject is sharp, but the background melts away. A narrow aperture (like f/16) lets in less light but keeps far more of the scene in sharp focus, ideal for landscapes where you want everything from the foreground to the distant mountains to be crisp.
Beginner tip: For portraits, try f/2.8 or wider. For landscapes, try f/8 to f/11 as a starting point
Shutter Speed
Shutter speed controls how long your camera's sensor is exposed to light, or more precisely, how long the shutter curtain remains open. It is measured in fractions of a second (or whole seconds for longer exposures). A fast shutter speed like 1/1000s or faster freezes motion completely, perfect for sports, wildlife, or any fast-moving subject. A slow shutter speed, like 1/15s or longer, allows motion to blur within the frame, creating the silky waterfall effect you have likely seen in landscape photography.
Shutter speed also affects camera shake. As a general rule, try not to handhold a shot at a shutter speed slower than 1 divided by your focal length. Shooting at 50mm? Try to stay at 1/50s or faster. Drop that and camera shake, the tiny, involuntary movement of your hands, below starts to appear as blur in the image.
Beginner tip: For everyday handheld shooting, 1/125s or faster is a safe baseline. For action, set the shutter speed to 1/500s or higher.
ISO
ISO controls how sensitive your camera's sensor is to light. A low ISO like 100 produces a clean, detailed image with very little digital noise. This is what you want when shooting in bright conditions. A high ISO, like 3200 or 6400, makes the sensor more sensitive, which is helpful in low light, but it introduces grain and digital noise into the image. The finer the grain's texture, the less distracting it tends to be. However, pushed too far, it can make images look soft and unusable.
Modern cameras handle high ISO remarkably well compared to even a decade ago. That said, ISO is still the setting you reach for last, after you have maximized your aperture and slowed your shutter speed as much as you can without introducing unwanted blur.
Beginner tip: Keep ISO at 100-400 when possible. Only raise it when your aperture and shutter speed have hit their limits.
How the Three Work Together
The real skill in photography is learning to balance all three settings in real time. Suppose you are shooting a child's birthday party indoors. The light is dim. Your first instinct might be to crank the ISO, and that is reasonable. But before you do, ask yourself: Can I widen my aperture to let in more light? Can I slow my shutter speed slightly, as long as the subject is not moving too fast?
Every adjustment has a trade-off. Open the aperture wider, and you reduce your depth of field. Slow the shutter speed, and you risk motion blur. Raise the ISO, and you add noise. Good photography is the art of choosing which trade-offs are acceptable for the image you are trying to make.
There is no universally 'correct' setting, only the setting that best serves the photograph you are envisioning.
A practical way to build this intuition is to practice shooting in Aperture Priority mode (Av on Canon, A on Nikon/Sony). Set your aperture, let the camera choose the shutter speed, and observe how the camera responds in different lighting conditions. Once that feels natural, try Manual mode and start making all three decisions yourself.
A Simple Exercise to Try
Find a subject with some texture — a brick wall, a flower, a friend's face. Set your camera to Manual mode and photograph the same subject three times, adjusting only one variable each time:
1. Keep ISO and shutter speed constant. Take shots at f/2, f/5.6, and f/11. Notice how the depth of field and brightness change.
2. Keep ISO and aperture constant. Shoot at 1/500s, 1/60s, and 1/15s. Notice the change in brightness and any blur.
3. Keep aperture and shutter speed constant. Try ISO 100, 800, and 3200. Zoom into the images and examine the noise.
This exercise will do more to cement your understanding than any amount of reading. Photography is a tactile craft, the knowledge lives in your hands as much as in your head.
Coming up Next Month on Frame by Frame
The exposure triangle is your foundation. Once it becomes second nature, once you can glance at a scene and instinctively know where to set your three dials, everything else in photography opens up. In the next installment of this series, we will move into composition: the rule of thirds, leading lines, and how to train your eye to find a strong frame before you ever raise the camera.
If you have questions as you practice, feel free to reach out. I am always happy to talk through what you are working on.
