We discuss the importance of the probe coherence volume in the interpretation of scattering data. The availability of low emittance synchroton radiation sources capable of producing highly monochromatic x-ray beams prompts one to consider the effects of partial beam coherence in the interpretation of diffraction experiments. It calls into question the analysis of data by deconvolution at the level of intensities.When the coherence volume approaches that of microscopically ordered regions in the sample new effects may be anticipated. For example, under strong absorption the intensity dependence on the incident energy may be used to locate the source of the scattering. Two examples are given. ; JRC.E-Institute for Transuranium Elements (Karlsruhe)