  The planetary nebula luminosity function (PNLF) technique for determining
distances to galaxies now has been applied to 34 galaxies, including 6 in the
Virgo cluster and 3 in the Fornax cluster. Of these, 16 galaxies are late-type
or spirals and presumably contain Cepheid variables useful for verifying the
PNLF method. For 7 of these galaxies, Cepheid distances exist; the PNLF
distances agree with the Cepheid distances within the dispersion of 8% and
within a zero-point offset of 1%. In addition, 3 small groups were studied (NGC
1023, Leo I, and Coma I) where both spiral and elliptical distances were
obtained to investigate the magnitude of any systematic dependence on spiral
versus elliptical Hubble type. None was found. Since the PNLF method agrees
well with the Cepheid system, and there is no measurable dependence on Hubble
type, it follows that PNLF distances to the ellipticals in Virgo and Fornax
also are on the Cepheid scale. This conclusion is strengthened by the Cepheid
distances to several Virgo galaxies and the recent determination of a Cepheid
distance to Fornax.
