  We investigate mesons containing charm quarks on fine lattices with a^{-1}
\sim 5 GeV. The quenched approximation is employed using the Wilson gauge
action at \beta = 6.6 and nonperturbatively O(a) improved Wilson quarks. We
present results for decay constants using various interpolating fields and give
preliminary results for form factors of semileptonic decays of D_s mesons to
light pseudoscalar mesons.
