I think that cognitive scientists would support the view that our visual system does not directly represent what is out there in the world and that our brain constructs a lot of the imagery that we believe we are seeing.

When the magic hour arrives, my thoughts center on light rather than on the landscape. I search for perfect light, then hunt for something earthbound to match with it.

And most of my early pictures failed but about one in a 100 somehow looked better than what I saw.

There is no question that photography has played a major role in the environmental movement.

I began taking pictures in the natural world to be able to show people what I was experiencing when I climbed and explored in Yosemite in the High Sierra.

Small, portable digital cameras that exceed the performance of an off-the-shelf Nikon using 35mm slide film are further away from current reality than the proposed NASA manned Mars mission, although I expect both to happen sometime during my lifetime.

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.