Manual Flash Question ..

[bigdazzler]

This may be a silly question but you never learn unless you ask ...

With a manual flash .. is each power increment say from 1/32th , 1/16th , 1/8th , 1/4, 1/2 , 1/1 .. are each of these intervals equivalent to 1 stop ??

[Empire]

Its 1/3 stops mate (assuming its the same as the canons)

[jev]

Its 1/3 stops mate (assuming its the same as the canons)

No, that is not what is asked, the question is on the light output of the flash not the clicks in your camera. Check the list in the back of the manual of your flash (this one is for the 580EX):

As you can see, power x 2 = guide number x √2. Since guide number = aperture x distance, if you double the power, you gain 1 stop. Or, each time you half the power, you loose one stop. So, yes, each interval on the flash is one stop.

[MarkChap]

Yes Darren you are correct

1/1 -> 1/2 is 1 stop less light 1/2 -> 1/4 is 1 stop

The canon speed lights make those adjustments in 1/3 stop increments
EG :- 1/1 -> 1/2 goes 1/1, -1/3, -2/3, 1/2, -1/3, -2/3, 1/4 etc

Onya Jev, got in before me and explained it better,

[TOM]

Dazza, sorry just got your pm a minute ago. have sent one.

[bigdazzler]

Thanks guys .. thought as much but wanted to be certain.

[Empire]

Sorry I misundertsood the Q, I was thinking the increments in manual mode are at 1/3 stops as opposed to are those 1 full stop. My bad.