When trying to take a portrait against a sunset, one of two things always happens 1) the subject becomes silhouetted because of the sunset behind them or 2) You use a flash, and the subject looks washed out.
so, what you do is
1) turn off your flash and aim at the sky
2) hold your shutter button halfway down ad get an exposure reading from the sky
3) while still holding down the shutter button, recompose the shot by aiming at the subject
4) turn the flash back on (keep holding down the shutter button!)
5) take the picture
this way, you get a beautiful sunset, and your subject gets fill flash and doesn't end up washed out!
so, what you do is
1) turn off your flash and aim at the sky
2) hold your shutter button halfway down ad get an exposure reading from the sky
3) while still holding down the shutter button, recompose the shot by aiming at the subject
4) turn the flash back on (keep holding down the shutter button!)
5) take the picture
this way, you get a beautiful sunset, and your subject gets fill flash and doesn't end up washed out!