Three-step excitation of the 6p(3/2)ns, nd, ng autoionizing Rydberg levels via the 6p6f 1/2[5/2](2) level of lead

New spectra of lead consisting of the autoionizing Rydberg energy region excited via the 6p6f 1/2[5/2](2) level is presented. Fifty levels along with their FWHM widths are reported. Eleven levels of the 6p(3/2)ng (6 less than or equal to n less than or equal to 12) configuration have been reported for the first time. Besides two unassigned levels with effective quantum number 8.446 and 10.86, five new levels of the 6p(3/2)9d configuration have been observed. An unexplained phenomenon is observed where the 6pns 3/2[3/2](2) levels for n > 14 do not show up via the 6p6f (1/2)[5/2](2) route in contrast to the fact they are observed as strong resonances when excited via other similar routes, namely, 6p7p 3/2[5/2](2), 6p8f 1/2[5/2](2) and 6p7f (1/2)[(5/2)](2) levels.