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. Blue filled dots are for H II regions with a diameter correction factor ≤50%, grey dots for all H II regions with no limits in diameter correction. The vertical dashed line shows the mean FWHM of the survey assuming galaxies at the distance of the main body of the cluster (16.5 Mpc). The blue solid line gives the bisector fit (Isobe et al. 1990) of the relation derived for H II regions with a diameter correction factor ≤50% (blue dots), the grey solid line for H II regions with no limits in the diameter correction.