I began to realise that film sees the world differently than the human eye, and that sometimes those differences can make a photograph more powerful than what you actually observed.

The combination of pictures and words together can be really effective, and I began to realise in my career that unless I wrote my own words, then my message was diluted.

What I mean by photographing as a participant rather than observer is that I'm not only involved directly with some of the activities that I photograph, such as mountain climbing, but even when I'm not I have the philosophy that my mind and body are part of the natural world.

One of the biggest mistakes a photographer can make is to look at the real world and cling to the vain hope that next time his film will somehow bear a closer resemblance to it.

There's no question that photographs communicate more instantly and powerfully than words do, but if you want to communicate a complex concept clearly, you need words, too.

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.