Isotope shifts of three lines of Hf I, lying in the red spectral region, ha
ve been measured by means of saturated-absorption spectroscopy in a hollow
cathode. Combined with experimental data, previously given in the literatur
e, and pseudo-relativistic Hartree-Fock estimates the field shifts (FS) of
six relevant configurations are deduced: FS (5d(2)6p(2)) = -84 mK, FS (6p(2
)6s(2)) = 36 mK, FS (5d6p(2)6s) = -28 mK, FS (5d(3)6p) = -90 mK, FS (5d(4))
= -94 mK and FS (5d6s(2)6p) = 12 mK, referred to 5d(2)6s(2). For these thr
ee studied spectral lines, connecting the configurations 5d(2)6s(2) and 5d6
s(2)6p the specific mass shifts are estimated to lie between 5 and 8 times
the normal shifts, using a King plot and pseudo-relativistic estimates for
the Vinti integrals, respectively.