I like the parallels between focusing light and focusing attention. When we look at something we focus our eyes. We flex our ciliary muscles to change the length and curvature of our lenses so what we are looking at come into sharp focus.
At the same time we are focusing our attention. We are looking and for at least moment or longer not thinking, just seeing.
That’s what we do when we take pictures. Seeing not thinking and then thinking about what we are seeing to make it a meaningful shot.