Relation between the Hα luminosity of individual H II regions corrected for [N II] contamination and dust attenuation and the equivalent diameter corrected for seeing effects. Coloured (cyan for cluster A and LVC, 16.5 Mpc; magenta for cluster B, 15.8 Mpc; green for W′ cloud, 23 Mpc; red for W and M clouds, 32 Mpc) dots are for H II regions with a diameter correction factor ≤50%, and the grey dots are for all H II regions with no limits in diameter correction. The vertical dashed lines show the mean FWHM of the survey assuming for the different substructures of the cluster. The coloured solid lines give the bisector fit of the relation derived for galaxies with a diameter correction factor ≤50%.