Flash control system, external flash and camera

摘要

A flash control system remotely controls an external flash by a camera. In the camera, a guide number is calculated as an exposure factor for the external flash, and a flash-light emission timing of the external flash is calculated. A built-in flash of the camera is controlled to emit two light signals at a time interval representing the guide number. The external flash detects the two light signals. A timing of a flash-light emission of the external flash is controlled in accordance with one of the two light signals. An amount of the flash-light emission of the external flash is controlled in accordance with the time interval.