My manual settings & equipment used:
ISO – 400 (late in the evening as sun is getting lower)
aperture – F 4.5
shutter speed – 1/200
lens – canon’s 85mm 1.2L (loving this lens)
camera body – canon’s 5d mark II
When taking a shot like this with a little one he is sitting down on a blanket and I am squatted down right in front of him (or sitting on my bootie). I have my camera set on one focal point in the center. And I am focusing on his eyes. I pretty much always focus on the eyes. I find you always want the eyes as sharp as possible. No one cares if the nose is more softly in focus but we always seem to want the eyes sharp and lovely.