Depth and illusion are two of the larger considerations in photographic composition. Photographs are two-dimensional representations of three-dimensional ideas. Our eyes are stereoscopic, giving us the perception of depth in our three-dimensional world. Photography is monocular vision that produces a two-dimensional
image. You need to rely on shadow and perspective to create the illusion of depth.
Visual effects create a connection between the elements of composition and our understanding of what is happening in the image. Although a photograph is two-dimensional and static, it can convey meaning that translates to height, width, depth, and time. In other words, a two-dimensional image conveys four dimensions of information through visual effects.
The space of a visual presentation is defined by the furthest and the closest points that we can see in that scene. A photograph against a plain background can be confined to the model herself. Compare that to a vast landscape where we can see elements that are very close, as well as the horizon. An interior environment can define the space of an image by showing the floor, walls, and ceiling. Where you fit your subject into that three-dimensional space is a crucial element of composition. A subject close to the camera will typically appear larger.