High-speed flash exposure with compact digital cameras

Abstract

A technique was developed to allow the use of external flash at image sensor exposure times lower than the manufacturer’s specified maximum sync speed of a compact digital camera. By correlating light meter measurements with brightness readings of a grey card, a method to use the digital camera image sensor to measure light from flash units was developed. The flash discharge curve was derived and integrated to develop a mathematical model for clipped flash output. Utilising experimental data, the model was validated and parameterised for flash units. A computer program was created to calculate settings for correct flash exposure.

Keywords:

• high-speed flash exposure
• measuring flash light
• clipped flash output