Photography is an artistic visual medium to EXPRESS. We express what we BELIEVE. Seeing is BELIEVEING. This chain of thoughts embarked me on a journey to understand how we really see. When I started, I had a very simple view about human vision and thought that eyes
are the most precious instrument in human vision. I couldn’t be farther away from the truth. In this article I will explore the salient features of human vision from the perspective of composition in photography.
A camera & human vision works differently. Camera as an instrument does a very simple job. It records a 2-dimensional projection of the 3D world. This recorded projection is an image. Human vision is a system comprising eyes (optical instrument), left and right Lateral Geniculate Nuclei (LGN), visual cortex.
LGN and visual cortex are designed to perceive (or recreate) 3-dimensional world from the 2-D information. Brain uses certain cues to perceive third dimension of depth such as perspective lines, Shadow, stereopsis, occlusion - objects in front hides the objects behind, relative size - closer objects appear bigger and farther objects appear smaller, texture gradient, light shading, defocus blur, accommodation. Retina has photo receptor cells Rods and cones. Rods are responsible for low light vision, colorless and peripheral vision (away from the subject that we are looking at
Central region (fovea) of the eye has high concentration of cones which are responsible for sharpness, colors and accuracy. Peripheral region has high concentration of rods to detect basic shapes, black & white vision and detect motion. This means that at a time eye looks at a very specific point of interest and then jumps to the next point of interest in a very quick movement (900 deg/sec!) known as saccades.
This is also why vignetting is pleasing in an image as it relieves the peripheral vision and helps to rest eyes on the subject.
A very large area of the brain is dedicated to see the world, make sense of it and interact with the environment. Complete occipital lobe, some parts of parietal lobe and some of the temporal lobe forms the visual cortex.
Visual cortex region V-1 in the occipital lobe has retinotopic map (pixel by pixel or cell by cell) of the visual data from the eyes. From here data is sent to higher visual regions into two streams called Ventral (downward) stream & Dorsal (upward) stream. The dorsal stream determines the spatial location and guides the motor system to interact with the environment. However, ventral stream deals with understanding and making sense of the data.
At this point it must be understood that each individual has different wiring (neural networks) in their brain. Though, everyone has all the regions but different regions may be more developed than others in different individuals depending on genetic & environmental factors. This is what causes the variety in interpretation of an image by different individuals and also remarkably different images from the same location by different photographers.
There are higher dedicated regions to analyze different aspect of visual data such as basic shapes and texture in V-2 region, speed and direction of motion (V5), color and spatial orientation (V-4), Para-hippocampus Place area (PPA) deals with scenery & landscape view while Fusiform Face Area (FFA) is specialized in facial recognition. Higher regions are more attention specific (foveal view) while V-1 takes into account complete field of vision.
I think this is clear indication why some people chose landscape photography over portrait & fashion and vice versa. As the data is relayed from V-1 to other regions, each region tries to make sense from the data by processing it as per the expertise and either pass onto the higher region or reject and discard the data as uninteresting.