B_MLR determined from spatially and spectrally degraded Stokes V profiles affected by noise, using calibration curves without macro-turbulent velocity (top row) and with a macro-turbulent velocity of 2.0 km s^-1 (second row). This is compared with the magnetic field strength B_MHD rebinned according to Eq. (3) (B_MHD−rebin, third row). We show an empirical approximation of the result of MLR, based on B_MHD−rebin and including the influence of the PSF in the fourth row. All profiles have been broadened with a micro-turbulence to match the widths of the profiles emerging from the MHD snapshot.