(User’s Manual – D300S page 169; D300 page 171)
The built-in pop-up flash has two types of flash metering:
i-TTL Balanced Fill Flash – The flash fires in two stages. Nikon calls stage 1 “monitor preflash”. The built-in flash emits a series of almost invisible flashes before the main flash burst fires (stage 2). The preflashes allow the 1005-pixel RGB flash sensor to examine all areas of the frame for reflectivity. The camera uses the Matrix meter and distance information from a D or G lens to calculate a flash output that is balanced between the main subject and ambient lighting.
Standard i-TTL – When the Spot meter is used the camera automatically switches to standard i-TTL. This mode ignores the background and concentrates on whatever ...