I did it once, and National Geographic recruited me. I did it primarily out of curiosity. A lot of legendary photographers had worked on that campaign. Ernst Haas had done the early photography, and I knew him. There's a lore in photography about that campaign, and I was curious.

My dad had been an ardent amateur photographer, and he taught me to compose a photograph from the back to the front, and then populate the picture.

Photography, alone of the arts, seems perfected to serve the desire humans have for a moment - this very moment - to stay.

Essentially what photography is is life lit up.

I started teaching in '76 and I'd been a photographer at the Geographic for six years. But prior to being at the Geographic I was a teacher. Plus my parents were teachers and my brother and my grandparents. So it was the culture of our family to think about teaching, to talk about teaching, to talk about teachers.

My first priority when taking pictures is to achieve clarity. A good documentary photograph transmits the information of the situation with the utmost fidelity; achieving it means understanding the nuances of lighting and composition, and also remembering to keep the lenses clean and the cameras steady.

It actually has transcended my career at the Geographic, so that when my career there ended, I had momentum as a teacher, and a belief in photographic education at the workshop level.