Comparison between the MZR derived with different strong line calibrations: PP04 O3N2 and M13 (orange diamonds), M08 (green crosses) and M91_corr (yellow circles). We use the formulation of the M91 calibration given by Kobulnicky et al. (2003), which takes into account the dependence of R₂₃ on the ionization parameter. In addition, we correct these metallicities following Pérez-Montero et al. (2013) to make them consistent with those derived using the direct method. We see that HCm and M91 relations show a similar trend in the whole metallicity range. Green lines are the Andrews & Martini (2013) MZR and ± 1σ uncertainties.