At least one prominent critic of photography appears to have assumed that from the invention of the daguerreotype in the 1830s, nineteenth-century photographers had total control over their photographic compositions and that consequently, we can understand their photographs solely in terms of their autonomous decisions regarding photographic technique. However, as Alan Thomas has indicated, to survive in their profession most nineteenth-century photographers, who were after all tradespeople, needed to have a strong commercial sense. Specifically, they needed to share and/or be influenced by the desires of their customers -just as twentieth-century professional photographers have had to satisfy the expectations of clients such as commercial publishers. Consequently, many nineteenth-century photographs reflect not only autonomous decisions on the part of photographers regarding technique, but also clients' desires and expectations regarding the visual content of photographic compositions; some of these expectations were influenced by prevailing conventions of painting, poetry, and theater. These considerations have implications for how we are to understand nineteenth-century photographs.

1. The passage is primarily concerned with discussing

A. the socioeconomic status of nineteenth-century photographers
B. nineteenth-century photographers' interest in the market for photography
C. the technical expertise exhibited by some nineteenth and twentieth-century photographers in their photographs
D. some of the conventions of painting, poetry, and theater that are to be found in the work of nineteenth-century photographers
E. some of the factors that are important the readers' understanding of nineteenth-century photographers