The red points show the r band luminosity function of galaxies estimated from the CALIFA MS, using absolute magnitudes from the SDSS M_r,p and with error bars representing Poissonian uncertainties only. The orange squares are for the same sample, but without the corrections for variations in cosmic density. The blue solid line shows the Schechter fit to the LF of Blanton et al. (2003), adjusted to our cosmology and redshift range. The vertical dashed lines indicate the completeness limits derived in Sect. 3.2. The faintest magnitude at which the luminosity function itself is marginally consistent with that of Blanton et al. would imply that the limit of completeness for the CALIFA sample is at roughly M_r,p < −18.6.