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AssigneeSeikosha Co., Ltd.
InventorsShigeru Tagami, Tomihiko Aoyama, Teruyo Hayakawa, Hiroshi Yamazaki, Yuji Nakajima, Seiichi Imano
Estimating the term…
A camera has a shutter which may also constitute a diaphragm. In a multi-flash mode the shutter selectively has a maximum aperture at an onset or at the end of the time base. The flash occurs in synchronism with a shutter waveform shaped by this aperture area and a time base element. In a second embodiment, a second diaphragm setting circuit is provided, in diaphragm priority photography, for computing a measurement value of a distance to a subject and a second diaphragm value from the guide number during an emission of flashed light. The diaphragm is set to the computed second diaphragm value, ad an electronic flash is energized with a desired aperture area. The diaphragm is set to an initial value to effect the photography at a time other than during the emission of flashed light. A timing circuit may be provided for setting the diaphragm to the second diaphragm value. The aperture area may be increased or decreased for diaphragm matching with the quantity of flashed light and the distance to the subject during diaphragm priority flash photography.
A flash synchronizing device comprising a shutter serving as a diaphragm, a multi-flash means for effecting a plurality of flashes during a period from a start of a single exposure by said shutter to the end thereof, means for setting said diaphragm to a series of different diaphragm values during said period, including a maximum diaphragm value, and a maximum diaphragm value synchronizing flash means for synchronizing one of the flashes of said multi-flash means with the time of occurrence of said maximum diaphragm value of said series during said period, at least one other of said plurality of flashes occurring at a time other than the time of occurrence of said maximum diaphragm value.
In a flash synchronizing device comprising a photometric means for measuring a brightness of a subject, a focusing means for measuring the distance to said subject, an exposure quantity setting means for setting an exposure quantity from a first diaphragm value obtained by said photometric means or predetermined by a user, a flash control means for operating an electronic flash a first time during a period from a start of a single exposure by the shutter to the end thereof, the improvement wherein said device further comprises a second diaphragm setting means for computing a second diaphragm value from the distance measured by said focusing means and from a light quantity of said electronic flash and for setting said second diaphragm value during said period, means for outputting the second diaphragm value to said exposure quantity setting means, and means for operating with flash control means a second time in synchronization with the time of occurrence of said second diaphragm value during said period.
A flash synchronizing device comprising a shutter serving as a diaphragm, a multi-flash means for effecting a plurality of flashes during a period from a start of a single exposure by said shutter to the end thereof, means for setting said diaphragm to a series of different diaphragm values during said period, including a maximum diaphragm value, and a maximum diaphragm value synchronizing flash means for synchronizing one of the flashes of said multi-flash means with the time of occurrence of said maximum diaphragm value of said series during said period, at least one other of said plurality of flashes occurring at a time other than the time of occurrence of said maximum diaphragm value, said means for setting said diaphragm comprising means for setting said diaphragm to said maximum value at the beginning of said period, whereby said one flash occurs at the beginning of said period.
A flash synchronizing device comprising a shutter serving as a diaphragm, a multi-flash means for effecting a plurality of flashes during a period from a start of a single exposure by said shutter to the end thereof, means for setting said diaphragm to a series of different diaphragm values during said period, including a maximum diaphragm value, and a maximum diaphragm value synchronizing flash means for synchronizing one of the flashes of said multi-flash means with the time of occurrence of said maximum diaphragm value of said series during said period, at least one other of said plurality of flashes occurring at a time other than the time of occurrence of said maximum diaphragm value, said means for setting said diaphragm comprising means for setting said diaphragm to said maximum value at the end of said period, whereby said one flash occurs at the end of said period.
In a flash synchronizing device for a camera having a shutter that also serves as a diaphragm, means for opening said shutter and controlling the diaphragm value thereof from the start of an exposure to the end thereof, a flash means, and means for controlling said flash means to produce a flash during said exposure, the improvement wherein said means for opening and controlling said shutter comprises means for controlling the diaphragm value to have a plurality of different values during said exposure, and said means for controlling said flash means comprises means for synchronizing said flash with the occurrence of a predetermined one of said diaphragm values or of a diaphragm value predetermined by a user and means for controlling said flash means to flash at another time during said exposure at which the diaphragm value is different than said predetermined one value.
In a flash synchronizing device for a camera having a shutter that also serves as a diaphragm, means for opening said shutter and controlling the diaphragm value thereof from the start of an exposure to the end thereof, a flash means, and means for controlling said flash means to produce a flash during said exposure, the improvement wherein said means for opening and controlling said shuttered comprises means for controlling the diaphragm value to have a plurality of different values during said exposure, and said means for controlling said flash means comprises means for synchronizing said flash with the occurrence of a predetermined one of said diaphragm values or of a diaphragm value predetermined by a user and means for controlling said flash means to flash at another time during said exposure at which the diaphragm value is different than said predetermined one value, said means for controlling said diaphragm comprises means for setting said predetermined one of said diaphragm values to have a maximum value greater than all other diaphragm values thereof during said exposure, said predetermined one of said diaphragm values occurring at the start of said exposure.
In a flash synchronizing device for a camera having a shutter that also serves as a diaphragm, means for opening said shutter and controlling the diaphragm value thereof from the start of an exposure to the end thereof, a flash means, and means for controlling said flash means to produce a flash during said exposure, the improvement wherein said means for opening and controlling said shutter comprises means for controlling the diaphragm value to have a plurality of different values during said exposure, and said means for controlling said flash means comprises means for synchronizing said flash with the occurrence of a predetermined one of said diaphragm values or of a diaphragm value predetermined by a user and means for controlling said flash means to flash at another time during said exposure at which the diaphragm value is different than said predetermined one value, said means for controlling said diaphragm comprises means for setting said predetermined one of said diaphragm values to have a maximum value greater than all other diaphragm values thereof during said exposure, said predetermined one of said diaphragm values occurring at the end of said exposure.
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
In accordance with both the intensity of the flash source and the distance of the flash source from the object, e.g. in accordance with the…
Digital circuits: for control of aperture
Apparatus or arrangements for taking photographs or for projecting or viewing them
Term ended 24 Apr 2012 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates generally to a flash synchronizing device. One embodiment of the invention is directed more particularly to the provision of a flash synchronizing device, in a camera with a multi-flash function, in which one of flashes is synchronized with the maximum value of the diaphragm. In another embodiment of the invention, a subject is properly irradiated with the flashed light when effecting diaphragm priority photographing.
Generally, when a flash synchronizing device is provided in a camera with a multi-flash function, a constant amount of light from the flash is emitted a plurality of times, in synchronization with shutter operations. The plurality of light emissions are effected at substantially equal intervals with respect to the time base, and are independent of the size of the aperture area of the shutter. For this reason, an average flash effect is obtained. The exposure quantity is the same for all portions of the picture, however, resulting in such drawbacks that vividness is not apparent in the photographed picture, and the photo is hard to see.
Elements for determining an exposure for taking a photo are the film sensitivity, the shutter speed, the diaphragm and the brightness of a subject. If the film sensitivity and the brightness of the subject are determined, a proper exposure value can be determined. Automatic exposure (AE) control is effected by setting the shutter speed and the diaphragm value so that a proper exposure C has an exposure value based on the subject luminance E, a film ASA sensitivity S, a diaphragm value F and an exposure time T.
In order that the invention may be more clearly understood, it will now be disclosed in greater detail with reference to the accompanying drawing, wherein:
FIG. 1 is a perspective view showing one embodiment of a flash synchronizing device according to the present invention;
FIG. 2 is a block diagram showing one embodiment of the flash synchronizing device according to the present invention;
One embodiment of a flash synchronizing device according to the present invention will hereinafter be described in detail with reference to FIGS. 1-5. In the flash synchronizing device of this invention, as illustrated in FIG. 1, a multiflash selecting switch SW.sub.2 is mounted on an upper surface of a body 1 incorporating a multi-flash function. Further, in addition to the multi-flash selecting switch SW.sub.2, a liquid crystal display unit 8, a release button 11 and a program selecting switch SW.sub.1 are mounted on the upper surface of the body. An AF unit 3 comprising a light receiving module 5 and a light emitting module 4, a finder 6 and an electronic flash 7, are provided on the front surface of the body 1. The body 1 is also equipped with a lens barrel 2.
The light receiving module 5 and the light emitting module 4 of the AF unit 3 are, as depicted in FIG. 2, connected to a CPU 20 via an AF interface 14 incorporating an A/D converting function and an electrooptical converting function. The program selecting switch SW.sub.1 and the multi-flash selecting switch SW.sub.2 are also connected to the CPU 20. When the program selecting switch SW.sub.1 is depressed with a light touch, a shutter speed priority mode, a diaphragm priority mode and an optimum exposure combination mode are sequentially selected under the program control. The selected program control is displayed on the liquid crystal display unit 8. When the multi-flash selecting switch SW.sub.2 is depressed with a light touch, a single flash mode, a #1 multi-flash mode and a #2 multi-flash mode are sequentially selected. The selected positions are displayed on the liquid crystal display unit 8. The #1 multi-flash mode is a mode in which the flash is synchronized with a program AE such that an aperture area comes to the maximum at an initial time, while the #2 multi-flash mode is a mode in which the flash is synchronized with a program AE such that the aperture area comes to the maximum at an end of the time base.
The release button 11 connected to the CPU 20 serves as a 2-step operation switch. A battery switch 16 is closed by a one-step operation with the result that a battery 15 is connected to the CPU 20. When the battery 15 is connected to the CPU 20, photometric and focusing operations are effected by an optical unit in the light receiving module 5 and the light emitting module 4 of the AF unit 3. An arithmetic circuit in the CPU 20 computes photometric and focusing data. The CPU 20 controls the shutter aperture 12 and a lens 2a of the lens barrel 2 through a shutter lens drive 13 on the basis of the arithmetic results.