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.

Above all, it's hard learning to live with vivid mental images of scenes I cared for and failed to photograph. It is the edgy existence within me of these unmade images that is the only assurance that the best photographs are yet to be made.

For example, in my dorm, at the University of Kentucky, I had the only camera. I don't think anyone came to college with a camera, other than me.

I'm interested in smokers standing on ledges, and big box stores, the rise of the suburbs, and the hollowing out of small towns. Self-storage. Things that didn't exist 50 years ago. Our common culture. What we have agreed is OK to live with.

I think that it's workshops, honestly, that have kept me keen about photography, and about my photography. My career as a workshop photographer came while I was at the Geographic in the late 70's, and has continued consistently since then.

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.

I will just say, appropriation is an intellectual idea until it happens to you. It's a philosophy, and it's got its own intellectual framework. Then there's what happens when it's your photograph. Then it's personal, and that's all I'll say.