Who is known for their expertise in photographic exposure and tonal range?

The correct choice is recognized for his significant contributions to the field of photography, particularly in understanding and manipulating photographic exposure and tonal range. Ansel Adams is acclaimed for his black-and-white landscape photographs, which often showcase the delicate interplay of light and shadow, allowing for a rich tonal range. His development of the Zone System was revolutionary, providing photographers with a method to control exposure and develop negatives to achieve the desired contrast and detail in their images. This system relies on precise calculations of exposure and tonal values, making it a fundamental technique in photography that remains influential today.

In contrast, the other choices are noted for different forms of art or photography; they may not specialize in photographic exposure. Georgia O'Keeffe is primarily known for her paintings, often focusing on flowers and landscapes in vibrant colors. Henri Cartier-Bresson is celebrated for his candid street photography and the concept of the "decisive moment," which emphasizes spontaneity rather than technical manipulation of exposure. Sandy Skoglund is known for conceptual art installations and photography that often features surrealistic scenes and staged environments, rather than focusing on the technical aspects of exposure and tonal range in traditional photography.