That statement [ Stephen Ambrose:'You, Sam, have the hardest job, which is, pretend like nothing has happened in the last 200 years.'] woke me up to the fact that the landscape that Lewis and Clark came across was greater than the Serengeti. And it's gone.

There are a lot of ways to be expressive in life, but I wasn't good at some of them. Music, for instance. I was a distinct failure with the cello. Eventually, my parents sold the cello and bought a vacuum cleaner. The sound in our home improved.

I had luck, but I worked hard and I suffered. It's not just photography I'm talking about. It's about whatever dream you want it to be.

That's who comes to my workshops. I jokingly tell my students that the class could be called "Your photographs: Better."

How the visual world appears is important to me. I'm always aware of the light. I'm always aware of what I would call the 'deep composition.' Photography in the field is a process of creation, of thought and technique. But ultimately, it's an act of imaginatively seeing from within yourself.

It's a little bit like talking about the life of writing. The life of writing may be about many things, but it always begins with the writer. With the kernel of an idea, or a character, or an idea or a theme, or even an outcome. But for documentary photographers, photographs begin at that intersection of the real world and the imaginative inner world.

I was asked by a student what my most significant accomplishment was at National Geographic, after thirty years, and I said that my career came to an appropriate close, and I still loved photography. Not everybody who spends their career at anything ends up fascinated and involved with it.