Sharpness is one of the first things viewers notice in a photograph, even if they don’t consciously realize it. A photo can have beautiful light and composition, but if the subject isn’t sharp where it matters, the image often feels unfinished or accidental.

Once you understand that light is everything, the next step is learning how your camera controls that light. This is where the exposure triangle comes in. Aperture, shutter speed, and ISO work together to decide how bright or dark a photo is—but more importantly, they shape how the photo feels.

If photography had a single rule that outweighed all others, it would be this: light matters more than your camera, your lens, or your settings. You can take a compelling photograph with an old phone if the light is right, and a forgettable one with the most expensive gear if it’s not.