Every photograph is the result of three camera settings working together: aperture, shutter speed and ISO. Once you understand how they interact, you can move from guessing to making deliberate creative choices.
The Exposure Triangle
The exposure triangle is a simple way to visualise the relationship between aperture, shutter speed and ISO. Each side controls how much light reaches the sensor, but each also affects the look of the image in its own way.
Aperture
Aperture is the size of the opening inside the lens. A wide aperture such as f/1.8 lets in lots of light and creates a shallow depth of field, which blurs the background. A narrow aperture such as f/16 lets in less light and keeps more of the scene sharp.
Shutter Speed
Shutter speed is how long the sensor is exposed to light. Fast shutter speeds freeze motion. Slow shutter speeds blur movement and can introduce camera shake if the camera is not stabilised.
ISO
ISO controls the sensor's sensitivity to light. A higher ISO lets you shoot in darker conditions but can add grain or noise. A lower ISO produces cleaner files in good light.
Making Creative Decisions
Start by asking what matters most in your photograph. If you want a blurred background for a portrait, choose a wide aperture first. If you want to freeze a runner, choose a fast shutter speed first. If you are shooting a landscape from a tripod, you can use a low ISO and a narrow aperture for maximum sharpness.
"Exposure is not about perfection. It is about the deliberate balance of light, motion and depth that serves your subject."
Practical Starting Points
Here are reliable starting points for common situations. Treat them as starting points, not rules.
- Portraits: f/1.8–f/4, 1/125s, ISO 100–400
- Landscapes: f/8–f/11, 1/15–30s, ISO 100–200
- Sports: f/2.8–f/5.6, 1/1000s, ISO 400–3200
- Indoor events: f/1.8–f/4, 1/60–1/125s, ISO 800–3200
Metering Modes
Your camera's light meter helps you judge exposure. Evaluative metering reads the whole scene, centre-weighted prioritises the middle of the frame, and spot metering reads only a small area. Spot metering is useful for backlit subjects and high-contrast scenes.
Final Tips
Shoot in raw format when possible. Raw files contain more information than JPEGs, giving you more flexibility when correcting exposure later. Review your histogram instead of relying on the brightness of the camera screen, which can be misleading in sunlight.
Key Takeaway
Master one setting at a time. Begin with aperture priority, then experiment with shutter priority. Manual mode becomes natural once you understand the trade-offs.