FEC vs Output power

[speed_dmon]

I wanted to try flash photography so I just received my 430EX II yesterday. I'm slowing getting the hang of it and have taken some good looking photos just playing with it and bouncing flash off walls and ceilings. My question is what is the difference between setting the flash exposure compensation and setting the flash output power. Are they completely independent of each other. I think I can recall from last night playing with it, that when the flash is in manual and power is adjusted, adjusting the FEC did nothing.

 

[Big Mike]

FEC adjusts the power output in relation to the metered value when in E-TTL (auto flash) mode. The flash fires a pre-flash and the camera meters it, it then comes up with a flash power that will work in conjunction with the aperture and ISO that are set for the shot. When you adjust the FEC, you are adding to or subtracting from that metered power value.

When in the manual setting, there is no metered value...just the power setting that you have chosen. So when in manual mode, there is no FEC.

 

[speed_dmon]

FEC adjusts the power output in relation to the metered value when in E-TTL (auto flash) mode. The flash fires a pre-flash and the camera meters it, it then comes up with a flash power that will work in conjunction with the aperture and ISO that are set for the shot. When you adjust the FEC, you are adding to or subtracting from that metered power value.

When in the manual setting, there is no metered value...just the power setting that you have chosen. So when in manual mode, there is no FEC.

Thanks big mike, that totally clears things up :thumbup: