Manual Flash (M) - Sony alpha HVL-MT24AM Mode D'emploi

Manual flash (M)

Normal TTL flash metering automatically adjusts the flash intensity to provide
the proper exposure for the subject. Manual flash provides a fixed flash intensity
irrespective of the brightness of the subject and the camera setting.
 In manual flash mode, the maximum flash power is when the manual flash
control is set to 1/1. Each step of the flash power level corresponds to one
aperture stop. Changing the setting by one stop, for example from 1/1 to 1/2, is
equivalent to decreasing the aperture one stop, for example from f/4 to f/5.6.
 Manual flash can only be used when the camera is in the M mode. In other
modes, TTL measuring is automatically selected.
 As manual flash is not affected by the reflectivity of the subject, it is convenient
for use with subjects with extremely high or low reflectivity.
TTL flash metering
1
Select M mode on the camera.
2
Press the TTL/M/Test button to light on the M (manual-
flash control) lamp.
The modes change in the following order. (Test flash (p. 40), Modeling flash
(p. 41))

Manual flash metering