Shear-ratio test of two populations of galaxies that are sheared by the same lens, i.e. z_far >  z_near >  z_d with source redshifts in consecutive bins. The dotted lines separate shear-ratios from different lens galaxies, while source redshifts increase from left to right which is highlighted by color code. Each color represents a combination of two sources at z_near and z_far. Ideally the outcome of the SRT (12) is zero. Data is taken from ray-tracing through the Millennium simulation. The shear estimator is defined in Eq. (11) with and θ_out  =  5′. Errors are obtained by a Jackknife method from the 64 different realizations per redshift. Left panel: all simulated galaxies have been used. Right panel: a magnitude cut of 24 mag in the r-band is applied for the lens galaxies.