Not all light sources are perfectly incoherent or perfectly coherent. Some light sources lie somewhere in the middle and, thus, are partially coherent. Using Diffraction Image Analysis, images of partially coherent sources can be generated. The degree of partial coherence is specified by a Gaussian or Sinc Gamma function. The user has control over the overall width of the Gamma function used in the analysis. For small Alpha values, which produce narrow Gamma functions, use the Mostly Incoherent analysis method. For large Alpha values, which produce broad Gamma functions, use the Mostly Coherent analysis method. Always verify that the sampling of the PSF is sufficient to assure accurate partially coherent results.