Aperture, shutter speed, and ISO are often called the exposure triangle, but the name makes them sound more complicated than they are. Together they decide how much light reaches the sensor and how motion is recorded. Learning them one at a time, with the same subject photographed at different settings, is more useful than memorising a chart.
Aperture controls depth of field
Aperture is the size of the opening in the lens. A wide aperture, shown by a small f-number such as f/2.8, lets in more light and creates a blurred background, which suits portraits. A narrow aperture, such as f/11, keeps more of the scene sharp, which suits landscapes. The trade-off is light: a narrow aperture needs a slower shutter speed or a higher ISO to keep the photo bright enough. Try photographing the same subject at f/2.8, f/5.6, and f/11 and compare how much of the background stays sharp.
Shutter speed controls motion
Shutter speed is how long the sensor is exposed to light. A fast speed such as 1/500 of a second freezes movement, which helps with sport and children playing. A slow speed such as 1/30 of a second can blur movement, which can show flowing water or light trails, but it also increases the risk of camera shake. When you are handholding a camera, a simple starting point is to keep the shutter speed at least as fast as the focal length you are using, for example 1/50 for a 50mm lens. related guide may help you decide which camera features make manual practice easier.
ISO is a brightness compromise
ISO controls how sensitive the sensor is to light. A low ISO, such as 100, gives the cleanest image in bright light. A higher ISO, such as 3200, lets you photograph in darker rooms, but it can add grain, called noise. Modern cameras handle high ISO much better than older models, so do not avoid it entirely. Instead, test your own camera at several ISO values and decide how much grain you accept. In practice, choose aperture for the look you want, shutter speed for the motion you want, and ISO to make the exposure work. another guide in this category shows how to keep the colours consistent after you have taken the photos.
To practise, choose one subject and photograph it at three different apertures, then at three different shutter speeds, keeping notes on each setting. Comparing those files side by side teaches the trade-offs faster than reading about them. Once the three controls feel familiar, try manual mode for a full session, and do not worry if early photos are imperfect; every photographer learns exposure by testing, reviewing, and adjusting.