Is the built-in flash's power adjustable?

[dRebelXT]

While shooting my toy car with flash on, using Macro mode with 350D, the shutter speed
was F/4, ISO 400 and 1/60s. When I manually set F/4, ISO 400 in AV, the shutter speed
was 1/15s. Does my 350D adjust the power of built in flash?

 

[jeremyftk]

Don't think so. I think the camera merely compensates for the apperture value IIRC.

 

[dRebelXT]

Maybe the flash only lasts 1/60s and the intensity of light when flash is on is 100s of times
larger than my room light, so during the additional 3/60s in AV Mode, little light got into the
camera.

 

[drumma]

shooting in P mode and Av mode gives diff shutter speed i realised. in P mode, it's 1/60.
in Av mode, it depends on the sync speed setting.

if i'm not wrong, there is an option to adjust flash power called FEC? my 10d does have FEC and noticable difference -1, 0 and +1 FEC.

FEC is flash exposure compensation.

 

[catchlights]

Maybe the flash only lasts 1/60s and the intensity of light when flash is on is 100s of times
larger than my room light, so during the additional 3/60s in AV Mode, little light got into the
camera.

Please read you camera manual for flash duration, if you set speed at 1s, or 1/60s (camera lens at same f-stop), the flash output will still be the same, what other factor the exposure when you shoot with flash on different shutter speed is the ambient light. if you need to adjust the flash output, you can use the flash compensation setting.

 

[Del_CtrlnoAlt]

i think my KM D7D can... ;p