Polaroid Corporation

Alan D Feinerman

Donald L Grimes

Kathy J Messina

A microcomputer is employed in an automatic exposure control system for developing and controlling execution of film exposure strategies for both ambient light exposures and flash and fill flash exposures wherein the scene is illuminated with a mixture of ambient light and artificial illumination provided by a photoflash lamp which may have light output characteristics that deviate from specification due to manufacturing variances. Using pre-exposure scene brightness and distance inputs the computer selects an appropriate one of a plurality of different preprogrammed trajectory signal programs which is to be fed to a stepper motor that drives a shutter blade mechanism in a manner whereby its operation is characterized by an aperture size versus time trajectory curve defined by the selected program. During the course of an exposure interval scene brightness level, including the flash contribution is monitored and is fed back to the computer which is programmed to regulate the provision of trajectory signals to the stepper motor so as to adjust the trajectory curve for optimum exposure in a manner that compensates for variations in the output characteristics of the photoflash lamp.

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Cambridge, MA, United States of America

Alan D Feinerman