Polarization interference filters that employ crystals with a strong dispersion of birefringence as the wave plates can provide a very narrow band pass width by using very thin crystal plates. If in addition, the birefringence is small, this filter can accommodate a very wide field-of-view. It is noted, in particular, that CdS exhibits a strong dispersion in the spectral regime between 5200 Å and 5400 Å, with a rate of dispersion that could provide a passband of only 1 Å with a filter structure of several millimeters thick. This paper investigates the properties of these filters. The results are presented and discussed.