The concept of Perspective
When we see a photograph on computer screen or on prints, we are looking at a 2-dimensional representation of a real 3-dimensional scene. And that is what photography is all about – capturing a 3D scene onto a 2D image. In fact, it’s amazing to know how photographers demonstrate “depth” or sense of “scale” in a (good) photograph. They use the concept of Perspective. This is one of the tricky areas of photography which if a photographer is not consciously aware of, can produce unwanted “distortions” or “flat” uninteresting images. 3D is real. A 2D depiction of a 3D scene is just an illusion exploiting how our brain synthesizes information to determine the “depth” in real-time.
Perspective in photography can be defined as the sense of depth or spatial relationships between objects in the photo, along with their dimensions with respect to the viewpoint (camera lens or the viewer).
(“night bus” captured by David Hobcote, viaPictureCorrect Photography Tips)