When the light is right and everything is working for me, I feel as tense as when making a difficult maneuver high on a mountain. A minute - and sometimes mere seconds - can make the difference between a superb image and a mundane one.

My interest in photography did not begin with books or mentors, or with any burning desire to see the world through a camera. It evolved from an intense devotion to mountains and wilderness that eventually shaped all the parts of my life and brought them together.

Ever since the 1860s when photographers travelled the American West and brought photographs of scenic wonders back to the people on the East Coast of America we have had a North American tradition of landscape photography used for the environment.

I find it some of the hardest photography and the most challenging photography I've ever done. It's a real challenge to work with the natural features and the natural light.

At the heart of all photography is an urge to express our deepest personal feelings - to reveal our inner, hidden selves, to unlock the artist. Those of us who become photographers are never satisfied with just looking at someone else's expression of something that is dear to us. We must produce our own images, instead of buying postcards and photo books. We seek to make our own statements of individuality.

The most interesting parts of the natural world are the edges, places where ocean meets land, meadow meets forest, timberline touches the heights.

My first thought is always of light.