The eye is the jewel of the body.
—HENRY DAVID THOREAU
You can observe a lot just by watching.
Photography is a human activity that depends entirely on the capabilities and limitations of the human visual system. We judge the apparent resolution, brightness, contrast, and the quality of color in photographs; but these attributes are subjective since everything depends on perception. Our vision results from a combination of physiology and psychology which correspond roughly to the eye and the brain. Of course, all eyes are not the same, but a typical or standard observer must be assumed to exist by those designing photographic ...