The article analyses the impact of the teaching of an ICT activity by a teacher educator. The authors traced two student teachers' transformations of the ICT activity in lessons during their school practice. They show how tracing the transformation of an ICT activity from a university session to school lessons can make the dilemmas associated with subject knowledge, learning, and pedagogy more visible for teacher educators. The study suggests that ICT creates an additional layer of complexity within teaching while also allowing the process and problems of learning to be more visually evident to a researcher.