Exposure
	As the name suggests, exposure is to expose the film/sensor. exposure or exposure value is the combination of aperture and shutter speed at a given ISO. For example, f5.6 at 1/60th sec on ISO100
	About Exposure
	Ways of metering-incident-reflected and grey card
	Camera metering modes
	Metering modes comparison
	Difficult metering situations
	reciprocity effect and failure
	choosing exposure for effect
	Zone system