Exposure is the deceptively simple concept at the very heart of photography. It has always been a subject of fascination to aspiring amateurs and professional photographers alike. Recent developments in digital technology have transformed the ways in which exposures can be manipulated, and this in turn has forced photographers to think about what they can achieve by understanding the variables of aperture, ISO and time.

Michael Freeman, professional photographer and author, with more than 100 book titles to his credit, was born in England in 1945, took a Masters in geography at Brasenose College, Oxford University, and then worked in advertising in London for six years. He made the break from there in 1971 to travel up the Amazon with two secondhand cameras, and when Time-Life used many of the pictures extensively in the Amazon volume of their World's Wild Places series, including the cover, they encouraged him to begin a full-time photographic career.

Since then, working for editorial clients that include all the world's major magazines, and notably the Smithsonian Magazine (with which he has had a 30-year association, shooting more than 40 stories), Freeman's reputation has resulted in more than 100 books published. Of these, he is author as well as photographer, and they include more than 40 books on the practice of photography - for this photographic educational work he was awarded the Prix Louis Philippe Clerc by the French Ministry of Culture. He is also responsible for the distance-learning courses on photography at the UK's Open College of the Arts.