Effect of redshift measurement errors on the luminosity function as found using mock MUSYC catalogues, analysed in three redshift bins (increasing from left to right). In all panels, the triangles show the true, evolving r-band ETG LF of the full simulation box. Top panels: LFs calculated using the 1/V_max weighting method. Filled circles show the results from using the true redshifts in the mock catalogues, the solid lines indicate the results when adopting photo-zs, the dashed lines shows the effect of a further convolution with the photo-z errors. Bottom panels: the filled circles are as in the top panels. The solid lines correspond to the PML estimates of the LF from the mock, the dashed lines to the photo-z based maximum likelihood estimator (C09). Shaded areas and vertical dashed lines are as in Fig. 1. The vertical dotted line shows the magnitude above which the recovery of the LF using the true redshift starts to degrade. Errorbars show Poisson uncertainties.