  Using photometric redshifts we determine the galaxy population of the
clusters of galaxies Cl0016+16 at z=0.55, Cl1600+41 at z=0.54, Cl1601+42 at
z=0.54 and MS1008-1224 at z=0.31. Comparing the clusters, we find no evidence
for a universal shape of the total luminosity function (LF) at these redshifts.
When dividing the LFs into spectral types, we find that the LF of the
early-type galaxies alone can be described by a Gaussian, while the LF of the
late-type galaxies is well fitted by a Schechter function, suggesting that the
separate LFs for different populations may be universal. The difference in the
total LFs can mainly be attributed to the varying relative normalisation of
these populations, implying that clusters with an abundant population of
late-type galaxies also have steeper faint-end slopes. In MS1008-1224 we detect
a faint blue population that dominates over a population with colours
consistent with dwarf ellipticals, opposite to clusters at lower redshift.
Compared to low redshift clusters, we find that a general fading of the
late-type population by ~2 mag and the early-type population by ~1 mag
describes the evolution from z=0.55 to z=0 well. As a consequence of the
different early-type and late-type LFs and their dependence on cluster radius,
the fraction of blue cluster galaxies, as measured by the Butcher-Oemler
effect, differs between the clusters and depends on limiting magnitude and
radius. We find a correlation between the dwarf-to-giant ratio and the surface
density, indicating that the high density environment in the cluster cores is
hostile to dwarf galaxies.
