flash compensation

[reemas]

i tired this and notice the obvious difference in picture quality.

however, what exactly does this do? i notice this isnt compensating any part of the exposure. so does it make the flash weaker and stronger? how does it compensate?

and when taking flash photos, is it better to use flash compensation or exposure compensation?

thanks for the help.

[Ken Fong]

I'm not an expert, but I think flash compensation affects the flash intensity (brighter, dimmer)...your histogram will creep right as you increase the compensation.
If you use exposure compensation, you are messing with the shutter speed, which may or may not be in sync with the flash duration...it will probably also depend on which mode you are using.
Perhaps flash compensation is to alter your subject's exposure, while exposure compensation is more to alter the background's exposure.

[reemas]

can anyone cofirm or deny the brighter / dimmer flash suggestion?

[PacAce]

can anyone cofirm or deny the brighter / dimmer flash suggestion?
Yes, Ken is correct.

The camera controls the flash exposure by controlling the duration of the flash, the longer the duration, the more powerful the exposure. When you use FEC to compensate for flash exposure, you are, in essence, telling the camera to lengthen (for +FEC) or shorten (for -FEC) the duration of the flash by the appropriate amount. FEC has no effect on the ambient light exposure with is set with the combination of aperture, shutter speed and ISO.

When you use EC, you are compensating for the ambient light exposure. To do this, the camea can change the shutter speed or the aperture or both, depending on which mode you are shooting in (except Manual, of course). EC has no effect on the flash output.

[reemas]

pacace.... THANKS!

[PacAce]

pacace.... THANKS!
Don't thank me. Thank Ken. All I did was confirm what he said. :)

[bauerman]

One of the best things about the Drebel hacked firmware isthe addition of flash exposure compensation - could not work without it at this point.....