Understanding power settings on flashgun, quick question.

[Dal]

Right, here's a quick question.

Say I've used these settings for a shot to get the right exposure.

1/250th
F5.6
ISO100
Flashpower 1/8th

If I then drop the aperture to f8 (1 stop down) then would I need to increase the flash power to 1/4th power to get the original exposure.

Think of this as a portrait shot.

 

[Steve Smith]

Correct. One stop down on the aperture lets in half as much light so the flash needs to have twice the power.

This is assuming that the majority of the light is provided by the flash and the ambient light is minimal.


Steve.

 

[Dal]

Correct. One stop down on the aperture lets in half as much light so the flash needs to have twice the power.

This is assuming that the majority of the light is provided by the flash and the ambient light is minimal.


Steve.

Brillaint, thanks Steve. Yeah it is assuming the lighting is just the flashgun.

Thanks