Chapter 3 - Basic Exposure (Non-Flash) Concepts

Abstract

This chapter explains the photographic variables related to exposure. It provides information required to control motion and eliminate blur in photographs. Determining the proper exposure for an image is an essential element of crime scene photography. Each exposure variable affects the others. One variable can be changed if another is also changed to maintain exposure equilibrium. The same overall exposure can be achieved with different exposure settings. This allows the photographer to capture a properly exposed image with different effects: different motion stopping capability and different ranges of depth of field. The exposure meter is the “tool” used to determine a proper exposure. It indicates whether a “proper” exposure has been established or whether the scene is currently overexposed or underexposed. Shutter speeds are not only exposure controls, but they also are motion controls. The proper choice of shutter speeds not only eliminates the risk of blurred photographs resulting from the movement of the photographer at the instant the shutter is depressed but can also eliminate the blur that can be caused by the movement of subjects and objects within well-composed photographs.