Shadow and Light
The way light hits the subject of a photograph has a profound influence on the resulting image. Lighting allows the contras of a photograph to be increased or decreased, hardened or softened, depending on whether slow falloff or fast falloff is used. I’m not huge on taking pictures of people, so here’s a picture I took of some clouds. I waited until the sun was almost visible over the top of the cloud, so the bottom would be dark:
Another picture I took is bright in the top-left, and gets progressively darker as you move down and to the right:
Another picture I took, uses fast falloff lighting, and is an actual picture of a light. In it, the subject is bright, and the background is completely dark:
Another picture I took incorporates the rule of thirds, with darkness. The top third is dark, the middle is bright, and the bottom is dark:
And again, with lines:
Lighting is key in taking a photograph. For an exaggerated example of how important it is, try to imagine the previous picture had it been taken at 12:00 noon.