Flash Control - Minolta DiMAGE 7i Instruction Manual

RECORDING MODE

FLASH CONTROL

ADI, pre-flash TTL, and manual flash controls are available. Flash control is changed in the basic
section of the recording-mode menu (p. 78).
ADI flash metering – Advanced Distance Integration. This mode combines distance information from
the autofocusing system with information from a pre-flash exposure. Unlike conventional TTL flash
metering, ADI is not influenced by the reflectance of the subject or background ensuring optimum
flash exposures.
Pre-flash TTL – calculates flash exposure with a pre-flash only. This mode must be used when using
close-up filters or filters that reduce the amount of light entering the camera such as neutral density
filters. Pre-flash TTL must be used when a diffuser is attached to the built-in flash or an external flash
unit.
The camera will automatically switch from ADI metering to pre-flash TTL when a low-contrast subject
is preventing the autofocus system from focusing. If the autofocus system cannot lock on the subject,
press the AF/MF button and manually focus; the ADI metering will remain in effect.
Manual flash control – fires the flash at full power, 1/4 power, or 1/16 power. The power output is
selected in the basic section of the recording-mode menu (p. 78). Because no pre-flash is used, man-
ual flash control can be used to fire slave flash units.
The chart lists approximate guide numbers for manual flash calculations. The following equations are
useful in determining the guide number, aperture (ƒn), or flash-to-subject distance required for expo-
sure.
Guide no. (for distance in meters / feet)
Camera sensitivity (ISO)
Manual
flash
100 200
Full 8 / 26 11 / 36
1/4 4 / 13 5.6 / 18
1/16 2 / 6.6 2.8 / 9.2
92
Guide no. = ƒn. X distance
400 800
16 / 52 22 / 72
Guide no.
8 / 26 11 / 36
4 / 13 5.6 / 18
= distance
ƒn.
Guide no.
distance = ƒn.