Brad don't know if you are aware of the formula for manual flash
430 EXII has a guide number of 43 mt at 105mm zoom and 100
ISO (don't forget to check your manual for the guide number at lower zoom settings)
Aperture = Guide Number divided by distance (to subject)
Therefore
Aperture = 43 / distance (lets say 10 mt )
Aperture = 43 / 10
Aperture = f4.3 (so f4)
Distance = Guide number divided by
aperture
Therefore
Distance = 43 /
aperture (lets say f8)
Distance = 43 / 8
Distance = 5.3 metres from your subject
Every step down in power on the flash is 1
stop less
light -
1/1 (full power)-> 1/2 = 1
stop
1/2 -> 1/4 = 1
stop.
Modifiers - umbrellas, bounce, stofen, gary fong etc all take away an amount of
light that you then need to allow for with either distance or
aperture.
Have fun learning, I know I am