When circumstances for university libraries changed drastically due to the covid-19 pandemic in 2020, video mediated reference service was used to maintain availability for library users. Many libraries used Zoom for this service. This thesis aims to investigate librarians' reference work via video calls, through a case study of a university library in Sweden. The study gathers librarians' experiences of communicating with users via Zoom, to gain knowledge about the work's characteristics and to discover possible strategies for managing video call services, and their inherent strengths and weaknesses, in a university library context. The study is based on six semi-structured interviews with university librarians who work at the Zoom desk. All respondents have many years of experience of working at a traditional reference desk, which enables valuable comparisons between the two working methods. The results reveal several advantages of Zoom, one of the biggest being the separate and undisturbed space that the Zoom desk represents. As a result of that, the respondents point out that Zoom has come to be used for in-depth reference service. By analyzing the interviews through the sociologist Erving Goffman’s theoretical framework of social interaction, and theories of social presence, we also hope to increase the understanding of the dynamics in video mediated communication.