This paper analyzes the epistemological dilemmas raises by the deployment of an ethnographic approach, from a poststructuralist perspective, in the research with children. We realize a bibliographical analysis on school ethnography and visual ethnography based on 70 academic publications (1957-2020). The research findings highlight: a genealogy of school ethnographies (1) and a typology of visual ethnographies (2). Both elements articulate around an epistemological analysis on relationships between who investigate and who is subject or object of knowledge.