A method (600) for detecting and tracking a feature of a web of packaging material (102), using a first capacitor (106) placed at a distance (d) from the web of packaging material (102) is provided. The method (600) comprises; feeding (602) a section of the web of packaging material (102) to a first position (p), so that the section influences a dielectric property of the first capacitor (106), measuring (604), at a point of time (t), a capacitance of the first capacitor (106), and determining (612) the feature of the section passing the first capacitor (106) at the point of time (t), based on the capacitance.