THE CAMERA OPERATING CHARACTERISTICS MOST FREQUENTLY QUOTED BY MANUFACTURERS OF MONOCHROME TELEVISION CAMERAS ARE (1) LIMITING RESOLUTION; (2) SIGNAL-TO-NOISE RATIO; AND (3) SENSITIVITY. THESE CHARACTERISTICS ARE RELATED TO EACH OTHER AND TO THE SCENE PARAMETERS OF SPATIAL FREQUENCY, CONTRAST, AND BRIGHTNESS. THE CAMERA CHARACTERISTICS ARE EVALUATED UNDER OPTIMUM LIMITING CONDITIONS OF THE SCENE PARAMETERS, AND HENCE DEFINE IN A GENERAL WAY THE QUALITY OF THE IMAGE PRODUCED, BUT THEY DO NOT GIVE MUCH INFORMATION ABOUT THE RANGE OF SCENE PARAMETERS OVER WHICH THE CAMERA WILL PRODUCE USEFUL PICTURES. THE CONTRAST TRANSFER FUNCTION AND THE RESPONSIVITY CURVE OF THE CAMERA GIVE ADDITIONAL INFORMATION ABOUT IMAGE QUALITY. A SIXTH CAMERA OPERATING CHARACTERISTIC, RELATIVE SPECTRAL RESPONSE, WHICH IS INDEPENDENT OF THE OTHER CAMERA CHARACTERISTICS AND THE SCENE PARAMETERS, ALSO MAY AFFECT IMAGE QUALITY. (AUTHOR ABSTRACT MODIFIED)