Scatter plots showing the recovery of the half-light radius measured from the single-Sérsic simulation. Each panel shows a different code. The main plot of each panel shows the relative bias per galaxy as a function of apparent I_E magnitude, while we summarise the bias distribution as a histogram on the right. The opacity is proportional to the density; the darker colours mean more points. The blue solid line highlights a zero bias for reference, and the grey dashed line represents the mean value of the bias for all magnitude bins together. The orange points indicate the running mean bias ℬ in bins of magnitude, with error bars representing the dispersion 𝒟 (see Sect. 3).