In recent decades, the reflection on the teaching practices has been considered as an important means among the teacher trainers. Nevertheless, chilean research note that the universities of this country have not achieved that students of Teaching Programs may develop reflections on their pedagogical procedures systematically. This situation is no far from the reality of students of Pedagogía Media en Ciencias Naturales y Biología from Universidad Católica de Temuco. They achieve only in some cases, and intuitively, reflections that may help them improve their performance. The purpose of this research is to strengthen the levels of students' reflection. In this context, the investigation is a qualitative one with a unique case study design. It points to the relevance of the use of class filming as a strategy which favors reflective processes on the pedagogical practice in collegiate contexts. It concludes that the participants appreciate the strategy of class filming, given that it favors the self assessment of their performance. Likewise, a mobility of the levels of reflection from the descriptive to the critic one, is shown. Nevertheless, it is important to highlight that the mobility depends on the time the participants spend on the reflective process.