The comparison between the EW Hα+[Nii] obtained in our spectroscopic survey with those obtained in imaging mode by Boselli et al. (in prep.) for 198 galaxies in common. Blue crosses are for star forming galaxies with a normal HI gas content (HI − def ≤ 0.4), open red circles for HI-deficient objects (HI − def > 0.4). Filled symbols indicate galaxies hosting an AGN. The solid line shows the linear fit EW Hα+[Nii]_spectra = 1.040( ± 0.058)EW Hα+[Nii]_imaging + 5.370( ± 1.766) (r = 0.79). The typical uncertainty in the equivalent width measured from spectroscopic data is 12 − 18%, in imaging mode is  ∼ 20%.