We have operated two types of CCD detectors over the past several years: the three-phase thinned Texas Instruments 800 x 800 and the thinned RCA 320 x 512. Both detectors are operated in a slow-scan, cooled camera behind a variety of optical instruments at ground-based observatories, often involving low light levels. Emphasis is placed on optimizing the camera's operation with respect to quantum efficiency, readout noise, charge-transfer efficiency, dark current, full-well satura-tion, bias image flatness, residual image, and on-chip binning. Techniques for optimizing these properties are discussed. Our camera system is described, and information about the performance of our five operational CCDs is given.