Digital imaging systems intended for use in quantitative cell image analysis must meet stringent requirements on both photometric and spatial resolution to support the type of investigations currently ongoing in the biomedical research community. There must be a match between the optics (microscope), the image sensor (camera), the image digitization and storage hardware, and the algorithms for quantitative analysis of the digitized images. Applicable theory from the fields of optics, electronics, statistics, and signal processing allows development of workable rules for designing such a balance.