Automatic exposure control system

Claim 2

A photographic control system for a camera, said camera having means for mounting photographic film material at a given focal plane so as to receive image-carrying rays transmitted along a given optical path from the scene to be photographed, and means for providing flash illumination and for determining the anticipated level of flash brightness of the scene expected from said flash illumination, said system comprising: means actuatable for unblocking and blocking said optical path and for defining a plurality of aperture values in operative relation to said optical path; means for cooperating with said unblocking and blocking means to establish operable aperture values in correspondence with anticipated levels of flash scene brightness determined by said determining means; energizeable means for defining exposure time intervals in correspondence with varying levels of actual scene brightness experienced during flash exposure operations; means when coupled to a source of power for actuating said unblocking and blocking means to unblock said optical path thereby initiating an exposure interval during which scene light is transmitted to said film plane and, in response to said exposure time interval defining means, to again block said optical path to thereby terminate said exposure interval; and selectively operative means for adjusting by substantially the same trim factor both said correspondence between said anticipated level of flash scene brightness determined by said determining means and said operable aperture values and said correspondence between said varying levels of actual scene brightness experienced during exposure operations and said exposure time intervals so that said system operates under substantially the same trim influence provided by said adjustment of the correspondence of both said operable aperture values and said exposure time intervals.

Claim 3

The system of claim 1 wherein said correspondence between said anticipated level of flash scene brightness and between said levels of actual scene brightness are predetermined in accordance with a given exposure value, and said adjusting means includes means for adjusting said correspondence by a trim factor substantially equal to a desired change in exposure value.

Claim 4

The system of claim 1 wherein said interval defining means includes means for sensing the brightness of the scene, and said unblocking and blocking means includes means actuatable for blocking and unblocking said brightness sensing means and for defining a plurality of secondary apertures in operative relation thereto, said secondary apertures being in tracking relation to said aperture values defined in operative relation to said optical path.

Claim 5

The system of claim 1 wherein said interval defining means includes means for sensing the brightness of said scene and for defining an interval in relation to the total brightness sensed thereby, said unblocking and blocking means includes a blade mechanism displaceable between a first position in blocking relation to both said optical path and said sensing means and a second position in unblocking relation to both said optical path and said sensing means, said blade mechanism defining progressively enlarging aperture values in operative relation to both said optical path and said sensing means as said blade mechanism is displaced to said second position, and said means for cooperating with said unblocking and blocking means includes means for cooperating with said blade mechanism to establish a primary aperture value in operative relation with said optical path and a secondary aperture value in operative relation to said sensing means in accordance with camera to subject distance.

Claim 6

A photographic control system for a camera, said camera having means for mounting photographic film material at a given focal plane so as to receive image-carrying rays transmitted along a given optical path from the scene to be photographed, and selectively operative means for selecting ambient or flash mode operation and operative in the flash mode for providing flash illumination and for determining the anticipated level of flash brightness of the scene expected from said flash illumination, said system comprising: means actuatable for unblocking and blocking said optical path and for defining progressively changing aperture values in operative relation to said optical path during said unblocking actuation; means operable only during said flash mode operation for cooperating with said unblocking and blocking means to establish operable aperture values in correspondence with anticipated levels of flash scene brightness determined by said determining means; energizeable means operable during both said ambient and said flash mode operations for defining exposure time intervals in correspondence with varying levels of actual scene brightness experienced during exposure operations; means when coupled to a source of power for actuating said unblocking and blocking means during both ambient and flash mode operation to unblock said optical path thereby initiating an exposure interval during which scene light is transmitted to said film plane and, in response to said exposure time interval defining means, to again block said optical path to thereby terminate said exposure interval; and selectively operative means for adjusting said correspondence between said anticipated level of flash scene brightness determined by said determining means and said operable aperture values, and between said varying levels of actual scene brightness experienced during exposure operations and said exposure time intervals so that said system operates in said flash mode under the trim influence provided by said adjustment of the correspondence of both said operable aperture values and said exposure time intervals while said system operates in said ambient mode under the trim influence provided solely by said adjustment of the correspondence of said exposure time intervals.

Claim 7

A photographic control system for a camera, said camera having means for mounting photographic film material at a given focal plane so as to receive image-carrying rays transmitted along a given optical path from the scene to be photographed, and selectively operative means for selecting ambient or flash mode operation and operative in the flash mode for providing flash illumination and for determining the anticipated level of flash brightness of the scene expected from said flash illumination, said system comprising: means actuatable for unblocking and blocking said optical path and for defining progressively changing aperture values in operative relation to said optical path during said unblocking actuation; means operable only during said flash mode operation for cooperating with said unblocking and blocking means to establish operable aperture values in correspondence with anticipated levels of flash scene brightness determined by said determining means; energizeable means operable during both said ambient and said flash mode operations for defining exposure time intervals in correspondence with varying levels of actual scene brightness experienced during exposure operations; means when coupled to a source of power for actuating said unblocking and blocking means during both ambient and flash mode operation to unblock said optical path thereby initiating an exposure interval during which scene light is transmitted to said film plane and, in response to said exposure time interval defining means, to again block said optical path to thereby terminate said exposure interval; and selectively operative means for adjusting said correspondence between said anticipated level of flash scene brightness determined by said determining means and said operable aperture values, and between said varying levels of actual scene brightness experienced during exposure operations and said exposure time intervals so that said system operates in said flash mode under the trim influence provided by said adjustment of the correspondence of both said operable aperture values and said exposure time intervals while said system operates in said ambient mode under the trim influence provided solely by said adjustment of the correspondence of said exposure time intervals.

Claim 8

The system of claim 5 wherein said exposure time interval defining means includes a photosensitive element, and said unblocking and blocking means includes means for controlling the input to said photosensitive element in substantially tracking relation to said aperture values.

Claim 9

The system of claim 5 wherein said interval defining means includes means for sensing the brightness of the scene, and said unblocking and blocking means includes means actuatable for blocking and unblocking said brightness sensing means and for defining a plurality of secondary apertures in operative relation thereto, said secondary apertures being in tracking relation to said aperture values defined in operative relation to said optical path.

Claim 10

The system of claim 5 wherein said interval defining means includes means for sensing the brightness of said scene and for defining an interval in relation to the total brightness sensed thereby, said unblocking and blocking means includes a blade mechanism displaceable between a first position in blocking relation to both said optical path and said sensing means and a second position in unblocking relation to both said optical path and said sensing means, said blade mechanism defining progressively enlarging aperture values in operative relation to both said optical path and said sensing means as said blade mechanism is displaced to said second position, and said means for cooperating with said unblocking and blocking means includes means for cooperating with said blade mechanism to establish a primary aperture value in operative relation with said optical path and a secondary aperture value in operative relation to said sensing means in accordance with camera to subject distance.

Claim 11

The system of claim 5 wherein said interval defining means includes means for sensing the brightness of the scene, and said cooperating means includes means for establishing operable aperture values substantially in accordance with camera-to-subject distance, and said adjusting means includes means for adjusting the correspondence between said operable aperture values and said camera-to-subject distance.

Claim 12

The system of claim 9 wherein said adjusting means includes means for simultaneously adjusting the amount of light rays passing from said scene to said sensing means.

Claim 13

The system of claim 5 wherein said adjusting means includes means for adjusting said correspondence between said anticipated level of flash brightness and said operable aperture values and said correspondence between said varying levels of actual scene brightness and said exposure time intervals by substantially the same trim factor.

Claim 16

The method of claim 12 wherein said adjusting step includes adjusting the functional relationship of said system to both said detected scene light and said subject-to-camera distance by substantially the same trim factor.