40d Problem/Question

[AE86]

Were you shooting in Auto mode or Manual (creative zone as Canon calls it)

In Auto you can't tell the camera which of the 9 AF points to focus on, in Manual you can.

I think P is like full Auto but you can tell the camera what points to use. I'm not to familiar with it, I stick to M or Av.

 

[visualpoetry]

When I shoot portraits of two people together, I use f/4.0 and dont have this problem. So I'm not sure I would blame it on DOF. My suggestion would be to increase your shutter speed. I guarantee they were moving around and 80 isn't fast enough. Lower your aperature to f/4.0 and increase your shutter speed. When shooting portraits (especially children that move around constantly) I always try to stay above 100.