should i leave the ceiling light on when using off camera flash?

[scottduffy]

I was wondering if i should be leaving the ceiling lights on when shooting portraits using a speedlight off camera? I was taking a few shots of my wife and niece but with the lights out the camera couldn't focus on them so i left them on and i'm not sure if this would affect the colour temp. I set my 50D to the flash setting for white balance.

 

[Arkady]

Won't make any difference unless you drag the shutter sufficiently to allow ambient light to register.

 

[scottduffy]

Thanks Rob.