Photometer

Claim 2

Exposure control system for a photo-taking apparatus for operation either in all natural light or with auxiliary synchronized flas light, in a camera having a focus adjustment, comprising: a photosensitive circuit inCluding at least two photosensitive elements connected in series and oriented to receive light from a field of view to be photographed, one of the elements receiving light from a portion of the field of view in which the object to be photographed is located and the other element receiving the light from the remaining portion of the field of view; a comparator circuit having two inputs for voltages to be compared, one of the inputs being supplied with the output produced at the junction of said elements, the other being supplied with a predetermined voltage; detecting means connected with said comparator circuit comprising a switching circuit having a predetermined threshold value, by virtue of said predetermined voltage, corresponding to the minimum difference in brightness between said object portion and said remaining portion of said field of view that requires use of auxiliary flash, and change-over means electrically connected with the switching circuit and selectively activated by the output of the switching circuit; auxiliary shutter-synchronized flash means; and exposure control means responsive to at least one of said photosensitive elements for regulating at least one of the factors of exposure time and exposure aperture, said exposure control means comprising means for adjusting at least one of (1) the timing of said auxiliary flash means and (2) the aperture diaphragm of said phototaking apparatus, in each case in accordance with the distance from the object to be photographed as given by the setting of the focus adjustment.

Claim 3

Exposure control system according to claim 1, in which said comparator circuit is a bridge circuit, said photoconductive cells constituting said photosensitive elements being connected with two arms of the bridge circuit and series connected resistor means being connected with other two arms of the bridge circuit, the output of the bridge circuit being derived from the junction of the cells and the resistor means.

Claim 4

Exposure control system according to claim 1, in which said change-over means is a caution lamp which is switched between turned on and off states to indicate whether synchronized flash is required.

Claim 5

Exposure control system according to claim 1, in which said auxiliary flash means includes a flash ready switch and said change-over means includes meand for operating said flash ready switch.

Claim 6

Exposure control system for a photo-taking apparatus in either all natural light or with auxiliary flash, in a camera having a focus adjustment, comprising: flash illuminating means having a flash ready switch and a flash trigger switch; a photosensitive circuit at least two photoconductive elements connected in series and oriented to receive light from an object to be photographed, one of the elements receiving light from a portion of the field of view in which the object is located and the other element receiving the light from the remaining portion of the field of view, the junction of said two elements providing an output corresponding to the difference of the brightness of said two portions; a comparator circuit having two inputs, one of the inputs being connected at least during one stage of the picture-taking operation with said junction of said elements to receive said output, the other input being supplied with a predetermined voltage; detecting means connected with the output of said comparator circuit and comprising a switching circuit having a constant threshold value by virtue of said predetermined voltage corresponding to the minimum difference of the brightness of said two portions of the field of view which requires phototaking with auxiliary flash, and change-over means electrically connected with the switching circuit and selectively activated by the output of the switching circuit, said detecting means being operatively connected with said flash ready switch for switching it on to make the flash illuminating means ready for flashing; and EXPOSURE control means responsive to at least one of said photoconductive elements for regulating at least one of the factors of exposure time and exposure aperture, comprising means for adjusting at least one of (1) the timing of said flash illuminating means and (2) the aperture diaphragm of said phototaking apparatus, in each case in accordance with the distance from the object to be photographed as given by the setting of the focus adjustment.

Claim 7

Exposure control system for a photo-taking apparatus in either all natural light or with auxiliary flash, in a camera having a focus adjustment, comprising: flash illuminating means having a flash ready switch and a flash trigger switch; a photosensitive circuit at least two photoconductive elements connected in series and oriented to receive light from an object to be photographed, one of the elements receiving light from a portion of the field of view in which the object is located and the other element receiving the light from the remaining portion of the field of view, the junction of said two elements providing an output corresponding to the difference of the brightness of said two portions; a comparator circuit having two inputs, one of the inputs being connected at least during one stage of the picture-taking operation with said junction of said elements to receive said output, the other input being supplied with a predetermined voltage; detecting means connected with the output of said comparator circuit and comprising a switching circuit having a constant threshold value by virtue of said predetermined voltage corresponding to the minimum difference of the brightness of said two portions of the field of view which requires phototaking with auxiliary flash, and change-over means electrically connected with the switching circuit and selectively activated by the output of the switching circuit, said detecting means being operatively connected with said flash ready switch for switching it on to make the flash illuminating means ready for flashing; and EXPOSURE control means responsive to at least one of said photoconductive elements for regulating at least one of the factors of exposure time and exposure aperture, comprising means for adjusting at least one of (1) the timing of said flash illuminating means and (2) the aperture diaphragm of said phototaking apparatus, in each case in accordance with the distance from the object to be photographed as given by the setting of the focus adjustment.

Claim 8

Exposure control system for phototaking either in all natural light or with auxiliary flash provided in a camera having a focus adjustment, comprising exposure control means for controlling at least one of the exposure factors of exposure aperture and exposure time for obtaining a proper phototaking exposure, a photosensitive circuit including at least two photoconductive elements connected in series and oriented to receive light from the phototaking field of view, one of the elements receiving the light from the portion of the field of view in which the object is located and the other element recieving the light from the remaining portion of the field of view, the junction of the two elements providing an output corresponding to the difference of the brightness of said two portions of the field of view; a comparator circuit having two inputs, one of the inputs being connected to said junction of said elements during at least one stage of phototaking to receive said output, the other input being supplied with a predetermined voltage; and detecting means connected with the output of the comparator circuit and comprising a switching circuit having a predetermined threshold value by virtue of said predetermined voltage corresponding to the minimum difference of the brightness of said two portions which requires phototaking with auxiliary flash, and comprising also change-over means responsive to said switching circuit operatively connected with said exposure control means so as to automatically adjust the exposure control means for auxiliary flash phototaking in accordance with the object distance given by the setting of said focus adjustment.

Claim 9

Exposure control system for phototaking either in all natural light or with auxiliary flash provided in a camera having a focus adjustment, comprising exposure control means for controlling at least one of the exposure factors of exposure aperture and exposure time for obtaining a proper phototaking exposure, a photosensitive circuit including at least two photoconductive elements connected in series and oriented to receive light from the phototaking field of view, one of the elements receiving the light from the portion of the field of view in which the object is located and the other element recieving the light from the remaining portion of the field of view, the junction of the two elements providing an output corresponding to the difference of the brightness of said two portions of the field of view; a comparator circuit having two inputs, one of the inputs being connected to said junction of said elements during at least one stage of phototaking to receive said output, the other input being supplied with a predetermined voltage; and detecting means connected with the output of the comparator circuit and comprising a switching circuit having a predetermined threshold value by virtue of said predetermined voltage corresponding to the minimum difference of the brightness of said two portions which requires phototaking with auxiliary flash, and comprising also change-over means responsive to said switching circuit operatively connected with said exposure control means so as to automatically adjust the exposure control means for auxiliary flash phototaking in accordance with the object distance given by the setting of said focus adjustment.

Claim 10

Exposure control system according to claim 6, in which said system further comprises: diaphragm means; means for setting the aperture of said diaphragm means to various aperture sizes, the setting means including a galvanometer having at least two windings, setting voltage means for applying a selected predetermined voltage to one winding of the galvanometer, and switching means operatively connected with the change-over means for selectively and electrically connecting said voltage setting means and said one winding of the galvanometer.

Claim 11

Exposure control system according to claim 7, in which said voltage setting means comprises means for applying to said galvanometer winding a voltage proportional to the flash output of the auxiliary flash.

Claim 12

Exposure control system according to claim 1 comprising also: a multistage shutter actuating means equipped to perform a succession of switching steps on sequence prior to effecting shutter release, including sequence switching means for switching the said inputs of said comparator circuit, said sequence switching means providing for connecting said comparative circuit to said junction of said photosensitive elements and to said predetermined voltage respectively in a first step, for connecting said inputs of said comparator circuit respectively to only one of said photosensitive elements and to a second predetermined voltage in a second step whereby said detecting means may be caused to activate said change-over means when the brightness of said one photosensitive element is below a predetermined value corresponding to said second predetermined voltage, and for providing in subsequent steps for connecting said one of said photosensitive elements to said exposure control means.

Claim 13

Exposure control system according to claim 6, comprising also: a multistage shutter actuating means equipped to perform a succession of switching steps in sequence prior to effecting shutter release, including sequence switching means for switching the said inputs of said comparator circuit, said sequence switching means providing for connecting said comparator circuit to said junction of said photosensitive elements and to said predetermined voltage respectively in a first step, for connecting said inputs of said comparator circuit respectively to only one of said photosensitive elements and to a second predetermined voltage in a second step whereby said detecting means may be caused to activate said change-over means when the brightness of said one photosensitive element is below a predetermined value corresponding to said second predetermined voltage, and for providing in subsequent steps for connecting said one of said photosensitive elements to said exposure control means.

Claim 14

Exposure control system according to claim 6, comprising also: a multistage shutter actuating means equipped to perform a succession of switching steps in sequence prior to effecting shutter release, including sequence switching means for switching the said inputs of said comparator circuit, said sequence switching means providing for connecting said comparator circuit to said junction of said photosensitive elements and to said predetermined voltage respectively in a first step, for connecting said inputs of said comparator circuit respectively to only one of said photosensitive elements and to a second predetermined voltage in a second step whereby said detecting means many be caused to activate said change-over emeans when the brightness of said one photosensitive element is below a predetermined value corresponding to said second predetermined voltage, and for providing in subsequent steps for connecting said one of said photosensitive elements to said exposure control means.