<title>Determining Light Intensity For Use With Intermittent Or Rotating Prism Cameras Utilizing A Cinematographic Light Intensity Translator</title>

Abstract

A problem at test ranges is the acquisition of valid light intensity measurements at remote camera tracking or fixed camera sites. After all instrumentation is set up and ready to go, one of the last things to be done is to determine what f/stops and shutter settings should be used. Known factors always exist, such as type of camera (intermittent or rotating prism), and type of film in use. Assuming the operator has no automatic exposure control, he now has to measure the ambient light. Keep in mind that not all personnel who track or set up cameras are professional photographers. The operator may use his light meter to take a reading, or it may have been forgotten, misplaced, or dropped, out of calibration, or have weak or no batteries. Or worse, he may use the light meter incorrectly. Use of the Cinematographic Light Intensity Translator eliminates the inconsistencies of range light measurements. The Range Camera Controller (coordinator) has the light measurement console at one central location with a primary sensor and remote sensors located as needed. By rotating a thumbwheel, the controller can select the output of a specific sensor at any given time. By looking at the CRT display, he can give any range camera operator the specific setting. Prior to the test, the controller enters all known camera factors for up to 50 functional stations into the minicomputer using the alphanumeric switch matrix on the control unit. The remote sensors, usually placed near the impact target or near ground zero, continuously generate and transmit the EV. All settings are given to the camera operators via rf radio net. At Tonopah Test Range (TTR), I have sent out changes within 90 seconds of drop or firing time without interrupting the test. The CRT also displays whether the film from each camera location needs to be under, or force processed.