Charge coupled imagers present special problems not encountered with beam-scanned sensors. This paper describes some of the instrumentation, procedures, and analyses used to evaluate charge coupled imagers. A simple analog technique for extracting signals from noise is discussed. Techniques are given for measuring and interpreting MTF (modulation transfer function), limiting resolution, temporal and spatial noise, image spreading, and image lag. Effects peculiar to CCDs (charge coupled devices) and CIDs (charge injection devices), such as aliasing and image smearing, are discussed.