Evolution of the photometric precision for raw data with the aperture radius according to different centring techniques in a complete dataset (e.g., AOR: 42614016). The 2D Gaussian adjustment (green asterisks) provides the best photometric precision for raw data in comparison to a centroid fit (magenta crosses), a double 1D Gaussian fit from the previously computed x- or y-FWHM (cyan boxes and red diamonds respectively), and a 1D Gaussian fit with a fixed FWHM (blue stars), in particular for small aperture radii.