ABSTRACT
Flash is an electronic device that is usually powered with batteries, but some use AC power and others can use either. For most applications, rechargeable batteries work just fine. Flash is the primary or dominant light, and available light serves as the fill-light. This technique is incredibly effective for photographing small birds and mammals in the forest when the available light is insufficient to permit fast enough shutter speeds to capture sharp images. Serious flash photography requires at least one or more flashes that are built by your camera's manufacturer, though some third-party companies also offer dedicated flash units, too. The camera's internal flash metering circuits measure the light output from a dedicated flash. When the camera determines the exposure is appropriate, it turns the flash off. Many cameras provide a way to use flash at shutter speeds that are faster than the X-sync speed, called "high-speed sync."
