Total magnification bias for halo-mass estimates as a function of limiting magnitudes that yield the local slopes α_d, s and lens redshift z_d (type of symbols). The source redshift is the same in all cases, i.e., z_s = 0.99. The mass difference δ_M is shown in colour code, where blue indicates underestimation, red overestimation, and white is an unbiased result. We cut off the colour bar for the largest deviations of 55% and 58% for α_d = 2.41 and z_d = 0.83 for higher contrast in the colour scale. The plot is roughly divided by the vertical line with α_d = 1 into mass underestimation for α_d <  1 and overestimation α_d >  1.