During the last decade the ever increasing demand for both high-quality optical coatings and virtually deterministic deposition processes has led to a large number of ion sources available for deposition purposes. For a successful implementation of an ion source the prime economic objectives process stability and production yield have to be considered. The economic efficiency is strongly dependent on the temporal stability and spatial distribution of the ion current density and ion energy spectrum. Retarding Field Analyzers have demonstrated their potential as a tool for the analysis of ion sources. However, deliberate evaluation of the measurements is required especially at a non-zero angle of incidence occurring during the examination of three dimensional ion emission profiles. The present study discusses the influence of different geometric Faraday-Cup designs on the resulting data as well as erroneous conclusions potentially drawn from measurements. Furthermore first results of the ion current density distribution characteristics of different ion sources, evaluated on the basis of data taken by a multicup array are presented.