Spectroscopic versus photometric redshifts for 4 clusters. We also give the dispersions around the mean relation (reduced value, classical value excluding galaxies for which the difference between spectroscopic and photometric redshifts is greater than 0.5), and the mean shift between photo-zs and speczs. The solid inclined lines give the perfect relation while the dotted lines give the  ±0.15 relations. The vertical lines give the position of the cluster along the line of sight.