Exploring human vision
We begin by looking at how human vision operates in order to understand our eyes as the primary tool of photography. Not only do our eyes work in particular ways to focus and frame our visual world, but all optical devices (cameras, scanners, etc.) depend upon or extend our visual acuity and limitations. An understanding of how you use your eyes, and their capabilities, helps you to make choices with other technologies. This chapter describes the basic anatomy of the eye-brain visual system, but also begins to look at how visual aids extend our biological tools. “The camera as viewer” describes how camera viewfinders, viewing systems, and lenses enable us to see. Beginning with the camera obscura, a darkened room that allows one to visualize the exterior world, we then continue with handheld cameras. Here, our focus is on how the camera can be used to orient the visual world vertically or horizontally; how the lens affects how much we can see and how much is in focus, and the scale or proximity of objects in relation to one another. The final section, “The camera as recorder,” describes different camera formats that record visual data, from small, medium, and large digital and film-based cameras, to instant and cellphone cameras, photocopiers, and scanners. In this section, we describe the available options, such as size of the film or sensor, storage ability, and processing capabilities, how to operate each camera body, and how to control components such as aperture and shutter.