I don't photograph my children often, partly because they're crazy and never stay still, partly because it's almost impossible to find a moment when one of them isn't climbing on me. When I do, one of my strategies for fast effective results is to go to a window, pre-focus on a spot on the floor and wait for them to come to me, as they always do when I have a camera in my hand. When they hit the spot, I shoot. If I'm really lucky, they'll pause, to stare at me long enough for me to get a bead on their iris. It's over in a split second but sometimes I get away with a little magic.