Manual Flash
Setting flash output as a fixed fraction of full power, so every frame receives an identical burst.
Formula / rule
Power = full / 2ⁿ
Measured in
fraction (1/1, 1/2, 1/4…)
In depth
Manual flash is the studio default because consistency matters more than adaptability: once metered, the light does not change between frames regardless of what the subject is wearing. Each halving of the power fraction is one stop, and lower power settings usually give shorter flash durations as a bonus.
Examples in practice
A head set to 1/4 power metering f/8 delivers exactly the same exposure on frame one and frame three hundred.