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US3286097A
|
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Photometric device having optionally selective response to light on two photoresistive cells
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US3304435A
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Photometric device having greater response to a preferential central portion of a scene
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US3212394A
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Photoelectric device for comparing different light intensities characteristic of a photographic scene
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US3121170A
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Light responsive unit having two acceptance angles
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US3091166A
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Photographic device responsive to both incident and reflected light
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Light responsive camera
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US3041929A
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Light valve structure
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Device utilizing a light valve actuated by a light acceptance unit
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Device with three dimensional light collector
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US2972930A
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Light meter device
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Illumination-quality indicator
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US2857807A
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Illumination balance meter for combined sunlight-flashlight photography
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US2870670A
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Exposure calculator for flash light photography
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Light meter
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Dual range exposure meter having a light-diffusing pivoted cover
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Device for use in determining photographic exposures
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|
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Method and apparatus for determining illumination contrast
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US2214283A
|
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Exposure meter
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US2080434A
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Illumination reflector for use in photography
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US1992233A
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Art of photography
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