Ansel Adams...

Figure 1

Ansel Adams was an American musician turned photographer around in the 20th century. His first published photographs were in club called Bulletin in 1922 and his first solo exhibition in 1928 (in a club in San Francisco).  In time, he came to favour photographing nature and was known for his photographs of Yosemite National Park.

Figure 2

His work mostly focuses on photographing epic landscapes, working only in black and white. He therefore tends to use a very deep depth of field in order to capture the entire landscape in focus (in order to see the details of the landscape). To capture this effect a wide angle lens (he used a 35mm) and a large f/stop.

Figure 3

Note how vast the landscapes are and how much of the photograph is in focus. In Figure 1 even the clouds in the distance. With a shallow depth of field the details such as the trees in the distance in Figure 3 wouldn't be captured. Only a very small aperture would be able to keep the rocks in the foreground AND the mountain in the background in focus in Figure 2.