In his article the author highlights the richness and topicality, for the study of uses, of a seminal work: Un Art Moyen. This book differs from Pierre Bourdieu's other works in its focus on the practical origins of popular norms. Rereading it today, we are struck by the hiatus between the first two chapters. The first constructs the model of photography as a family and identity practice, whereas the second transcends the '?family' unit of analysis and opens onto the study of '?practices' and their diffusion - subjects that have recently been put onto the agendas of fields as diverse as '?information and communication science' and '?practice-based studies'.