Group Photos - Focusing Help

I did family photos for my friend this summer, never having done it before obviously. My biggest concern was exposing it properly but I think I did ok with that - as I stared through the view finder I found I had no idea where to focus! My focus point was different on each photo and some are just bad - I was so upset with myself after all the research I did.

BTW, they waited too long to get started by which time the little ones weren't having it so the session lasted about 10 minutes and any group formation we had fell apart! Luckily they wanted casual cause that's sure what they got.

Q: I assume I would always focus on a face - which person's face should I have focused on in the two examples? (Aperture was 8.0)

What should I be taking into consideration in order to select the right focus point when the people are not organized into neat rows?

Q: I used a 17-55mm f2.8 lens but now I'm wondering if I should have used the 70-200L at about 80mm or the 100mm Macro. Would these have been better choices?

I ask because in one other standing image, I seem to have a lot of empty space at the sides of the group and wondered if my lens choice was incorrect. The attached images have been cropped to 8x10.

I've tried to find a definitive answer to the focus issue but cannot. It would help me to know what you would have done by relating to my own image. Thanks so much!!!

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Hey Pibb, I think that at f8.0 just finding a central face to focus on would work, as the narrow aperture will keep a lot more in focus. When it gets to f2.8 or smaller is where it gets tricky, as the DOF will be quite a bit smaller and if there is a big distance difference between faces more will get out of focus.

Thank you Roastpuff,

Looks like I was looking for answers in all the wrong places - now that they moved my post I see other similar questions in the posts of this section.

Central focus, ok.

In picture #1 that could be the dark-haired girl on the left, next to the standing toddler?

In picture # 2 it would be the toddler, since the dog is closer to me?

Maybe I'm fretting too much about all this, but what could be worse than pics that are out of focus - there are no second chances with these types of photos!

Thanks again / Pat