I like to shoot people photos, but I rarely DO because it is the most awkward kind of thing to shoot people who
invariably do not want to be shot. AS anyone here knows, it is far from my preferred form of photography.
But when I SEE something great, I will often focus on something at a similar distance and exposure level,
then turn on my heels and fire away, manually focusing as I shoot to get it right before the person becomes
aware of what is happening. This is the story here, the girl in the glasses figured it out and buried her face
in her friend's shoulder to escape me. But those 4 frames of 'hang time' before she reacted are perfect,
because you can see the brain working and still have the scene the way you wanted it. The picture above
was so different, in that I just pulled the camera up, focused (badly) and shot 2 frames and respectfully
left them alone. It works better this other way, I think.