Okay so here's my question. I understand aperture, ISO, and shutter speed. But I am trying to figure out is distance from my subject. For example, if I'm shooting a family of 4 at a f/1.8 ; how far away from them do I need to stand in order for them to be in focus? Also, what the ideal f/stop for shooting 1 person, 2 person, 3 persons etc- so everyone is in focus? I seem to always be getting someone out of focus in my photos at a low f/stop. I have see DOF calculators, but they just don't make much sense to me. Today, I am shooting my first maternity shoot and want to make sure that her whole body is in focus... so would I use the focus points and JUST focus on her face or would I use the focus points that focus on all of her body?? Thanks so much!!