Cubic Pd1-xInx and Pd1-xAlx (0.4 < x < 0.56) intermetallic compound films have been deposited on oxidized silicon wafers by r.f. sputtering using either a multizone target or two independent targets, The actual composition was determined by electron-probe microanalysis. The characterizations by X-ray diffraction show that the films crystallize in a beta-CsCl structure. This is the structure prescribed by the Hume-Rothery rule for an electron concentration of 1.5 valence electrons per atom. In non-stoichiometric compounds, constitutional point defects keep the rule enforced. The optical properties have been studied by normal incidence reflectivity and ellipsometry and have been interpreted in terms of a Lorenz-Drude model. The analyzed results show that the variations of the optical properties can be assigned to changes in the electronic density of states. These changes are caused by the point defects imposed by the deviation from stoichiometry.