Nikon SB-27 Front-curtain sync flash, Guide Number, Matrix Balanced Fill Flash, Monitor Preflash

Glossary of terms

Front-curtain sync flash

In normal flash synchronization, the Speedlight fires at the beginning of the exposure. The flash therefore fires just after the front-curtain opens. Rear-curtain sync flash is also possible with cameras featuring a rear-curtain flash sync mode set on the camera.

(Applicable to all camera groups)

Guide Number

This number refers to the maximum light output in units of GN [ISO 100 . m(ft)]. A guide number is given to help determine the correct aperture or f/stop value, or flash shooting distance using the following equation.

f/stop (aperture) =

guide number

flash-to-subject distance (m)

flash-to-subject distance (m)= guide number f/stop (aperture)

(Applicable to all camera groups)

Matrix Balanced Fill Flash

This mode automatically controls flash output so as to keep both subject and background perfectly exposed.

The camera's Matrix Metering System determines the correct exposure based on ambient light. Flash illumination brightens the main foreground subject but does not overpower the background.

(Applicable to F4-Series, F-801s/N8008s, F-801/N8008, Pronea 600i/6i, F-601/N6006, F-601M/N6000, F65-Series/N65-Series, F60-Series/N60, F50-Series/N50, and F-401X/N5005)

Monitor Preflash

In Automatic Balanced Fill-Flash with TTL Multi Sensor mode, immediately after you depress the shutter release button and before the shutter is activated, the SB-27 fires a brief series of nearly invisible preflashes known as Monitor Preflash. These preflashes are detected by the camera's TTL Multi Sensor, then analyzed for brightness and contrast ensuring optimal exposure.

(Applicable to F5, F100, F90X/N90s, F90-Series/N90, F80-Series/N80-Series, F70-Series/N70)

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