I did a story for the Geographic on Meriwether Lewis and William Clark, and Stephen Ambrose was the writer. He said, "I've got the easiest job in the world. I just have to re-tell the story of the greatest fishing, camping, hunting, canoeing trip of all time. You, Sam, have the hardest job, which is, pretend like nothing has happened in the last 200 years.

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.

The reason I don't want to say anything about it is it has a strange power to take over the conversation. Just like it's doing with us. I was asked to participate in a documentary about Richard Prince, and be the voice of someone who was appropriated, and I declined. The reason I did is I don't want it to be the subject of the discussion of my work.

For spiritual companions I have had the many artists who have relied on nature to help shape their imagination. And their most elaborate equipment was a deep reverence for the world through which they passed. Photographers share something with these artists. We seek only to see and to describe with our own voices, and, though we are seldom heard as soloists, we cannot photograph the world in any other way.

When assignments were over, photography continued. One of the primary reasons it did was that I wanted and needed to have fresh work. Also, it's very stimulating to be around non-professional photographers. They're the ones with the purest flame burning about their photography. I appreciate that.

I'm very involved in photographing America now, so I don't think of faraway places, as I did when I was young.

Yes, there are billions more photographers, and billions more photographs every day, but who's building up a point of view? Who's photographing with intention, and whose body of work will sustain itself and survive?