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.

When we tune in to an especially human way of viewing the landscape powerfully, it resonates with an audience.

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.

A lot of people think that when you have grand scenery, such as you have in Yosemite, that photography must be easy.

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.

I think landscape photography in general is somewhat undervalued.

I almost never set out to photograph a landscape, nor do I think of my camera as a means of recording a mountain or an animal unless I absolutely need a 'record shot'. My first thought is always of light.

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

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.

The reason that I keep writing is that all my most powerful messages about the fates of wild places that I care about need to have words as well as images.

Today, I'm very careful not to mention very specific locations when I write or give captions.

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.

Wanting to take a light camera with me when I climb or do mountain runs has kept me using exclusively 35 mm.

I like to feel that all my best photographs had strong personal visions and that a photograph that doesn't have a personal vision or doesn't communicate emotion fails.

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.

My mountaineering skills are not important to my best photographs, but they do add a component to my work that is definitely a bit different than that of most photographers.

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.

If we limit our vision to the real world, we will forever be fighting on the minus side of things, working only too make our photographs equal to what we see out there, but no better.

My first thought is always of light.

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

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'm exchanging molecules every 30 days with the natural world and in a spiritual sense I know I am a part of it and take my photographs from that emotional feeling within me, rather than from an emotional distance as a spectator.

I remember when an editor at the National Geographic promised to run about a dozen of my landscape pictures from a story on the John Muir trail as an essay, but when the group of editors got together, someone said that my pictures looked like postcards.

The landscape is like being there with a powerful personality and I'm searching for just the right angles to make that portrait come across as meaningfully as possible.

These days, most nature photographers are deeply committed to the environmental message.

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.

Luckily, many other people tell me how they have had a particular landscape photograph of mine in their office or bedroom for 15 years and it always speaks to them strongly whenever they see it.

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.

Roosevelt's magic lay in one facet of his personality: He knew how to take the risk. No other man in public life I knew could so readily take the challenge of the new.

To do the Ozzfest again would be great. I'd like to finish with a final Sabbath album. You always feel that it is still a challenge.

People are not perfect... very often the relationships that are strongest are those where people have worked through big crises, but they've had to work through them. So the challenge to us is to work through that.

Every single book is a challenge.

Critics are sentinels in the grand army of letters, stationed at the corners of newspapers and reviews, to challenge every new author.

The lopsided attitudes of college professors pose a serious challenge to learning because students are so susceptible to becoming lopsided sheep.

I really enjoy comedy. It's a real challenge.

I had a hard time with that hockey. I hadn't grown up skating, so that was my biggest challenge. We worked on it and worked on it. But then when we first shot it, it was so hard for me.

The challenge is to practice politics as the art of making what appears to be impossible, possible.

Change can either challenge or threaten us. Your beliefs pave your way to success or block you.

My greatest challenge has been to change the mindset of people. Mindsets play strange tricks on us. We see things the way our minds have instructed our eyes to see.

I'd say that it's important for music to be there that gives you a challenge, that rearranges things in your head.

I like good stories. Quality products and character are what's important. Even if the script isn't that strong, if I challenge myself with a great character, I'll go for it.

I tend to arrive in the rehearsal process with very strongly developed ideas about what I want to do. But I don't like those ideas to be things that are not subject to change, or subject to development, or subject to challenge.

I'm not looking to set a standard... but, I believe I have offered a challenge to others with my work.

If you live a life of make-believe, your life isn't worth anything until you do something that does challenge your reality. And to me, sailing the open ocean is a real challenge, because it's life or death.

And, I'd never done Tennessee Williams, and I had done Broadway musicals, so it was a challenge.

When you remove the risk, you remove the challenge. When you remove the challenge, you wither on the vine.

After Land I wanted to continue exploring the theme but I needed a new challenge so turned to colour. I explored Bradford and produced a series of urban landscapes that I liked, but because Land had made such an impact on the general public my colour work wasn't reviewed.

The worlds I paint leave a lot to engage the imagination by hinting at what lies beyond the four edges of the painting. I think getting beyond the four edges of an opportunity or challenge is one of the basic skills you need in business.

For me, it's a bigger challenge, it's much harder to do and much more rewarding to do well, then just to think up stuff of your own, hit or miss, because you've got to see to it that you don't torpedo any of his punch lines.