Photography is the art and science of capturing light to create images. The word itself comes from the Greek "phos" (light) and "graphē" (drawing), giving us "drawing with light." At its heart, photography is a technical craft built on three pillars that together control how much light reaches the sensor: aperture, shutter speed, and ISO, collectively known as the exposure triangle. Mastering how these three elements interact is the first step toward moving photography from a mechanical process into an expressive medium.
Each pillar of the triangle influences not only exposure but also the look and feel of the final image. Because the three are interdependent, every change in one must be balanced by a change in another to preserve the same brightness. Understanding this balance is what allows a photographer to begin making deliberate creative choices rather than simply recording whatever the camera decides to capture.