Flash photography system

• US 4,550,996 A
• Filed: 10/24/1983
• Issued: 11/05/1985
• Est. Priority Date: 10/22/1982
• Status: Expired due to Term

• Current Assignee: Minolta Camera Kabushiki Kaisha
• Original Assignee: Minolta Camera Kabushiki Kaisha
• Inventors: Inoue, Toru, Nakai, Masaaki, Taniguchi, Nobuyuki, Omaki, Takanobu, Hosomizu, Hiroshi, Sekida, Minoru, Niwa, Masatake
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US06/544,871
• Time in Patent Office: 743 Days
• Field of Search: 354/413, 354/414, 354/416, 354/417, 354/423, 354/422, 354/420
• US Class Current: 396/161
• CPC Class Codes: G03B 2217/005 Blur detection
• CPC Class Codes: G03B 7/08 Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
• CPC Class Codes: G03B 7/097 for control of both exposure time and aperture
• CPC Class Codes: G03B 7/16 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 "guide number" of the flash bulb and the focusing of the camera

Abstract

A flash photography system using a first aperture value output calculated from a desired diaphragm aperture value for flash light photographing with data obtained from ambient light, film sensitivity and the exposure data, a second aperture value output independent of the light value of the ambient light, data selecting circuitry for outputting any one of the first aperture value output and the second aperture value output, an aperture controller for controlling the actual diaphragm aperture size from the output of the data selecting circuitry, and means for producing a stopping signal to stop the emission of the flash light when the flash light emission reaches a predetermined value.

Claims

1. A flash photography system, comprising:

(a) first light measuring means for measuring ambient light;

(b) film sensitivity output means for producing a signal representing the sensitivity of the photographic film used in the camera;

(c) exposure time output means for producing exposure time data for flash light photography;

(d) first aperture value output means for calculating a desired first diaphragm aperture value for flash light photograpny based on the data obtained by said first iight measuring means, said film sensitivity output means and said exposure time output means;

(e) second aperture value output means for producing a second aperture value independent of the light value of the ambient light;

(f) data selecting means for outputting said first diaphragm aperture value or said second aperture value;

(g) shutter control means for controlling the camera shutter based on the exposure data of said exposure time output means;

(h) aperture control means for controlling the actual diaphragm aperture size based on the output of said data selecting means;

(i) means for effecting flash light emission;

(j) second light measuring means for measuring the flash light emitted to, and reflected from, a photographic object;

(k) means for integrating the output of said second light measuring means; and

(l) means for producing a signal to stop the emission of the flash light when the output of said integrating means reaches a predetermined value.

2. The flash photography system according to claim 1, wherein said data selecting means comprises means for selecting between the aperture value of said first aperture value output means and the aperture value of said second aperture value output means, depending on the output of said first light measuring means.

3. The flash photography system according to claim 1, wherein said second light measuring means is provided at a position to receive light reflected from the photographic object passed through a photographing lens and a diaphragm aperture of the camera and in turn reflected by the photographic film plane.

4. The flash photography system according to claim 1, wherein said second aperture value output means comprises means for producing aperture value data corresponding to a given film sensitivity, means for producing said given film sensitivity, means for calculating the difference between said given film sensitivity and the film sensitivity signal to produce a difference output;

and

aperture data output means for producing aperture data less, by said difference output, than said aperture data corresponding to said given film sensitivity.

5. The flash photography system according to claim 1, wherein said first aperture value output means produces the aperture value data for effecting an underexposure by a predetermined value with respect to the correct exposure value for ambient light photography.

6. The flash photography system according to claim 5, wherein said first aperture value output means further comprises means for producing a constant value corresponding to the sensitivity pattern of the light measurement of said first light measuring means, and means for calculating an aperture value representing a smaller aperture size by said constant value than that for the aperture value for effecting a correct exposure for ambient light photography.

7. A flash photography system, comprising:

(a) first aperture data output means for producing first aperture value data for flash light photography and corresponding to a given film sensitivity;

(b) film sensitivity output means for producing an output representing the film sensitivity of the photographic film used in the camera;

(c) second aperture data output means for producing second aperture value data modified by adding the difference between said given film sensitivity and said film sensitivity output to said first aperture value data;

(d) aperture control means for controlling the diaphragm aperture of the camera based on said second aperture value data;

(e) means for effecting emission of flash light;

(f) light measuring means for measuring the amount of flash light reflected from a photographic object;

(g) means for integrating the output of said light measuring means; and

(h) means for producing a signal for stopping the flash light emission when the integrated value of said integrating means exceeds a predetermined value.

8. The flash photography system according to claim 7 wherein said second aperture data output means comprises first signal output means for producing a first signal representative of said given film sensitivity, a subtractor for calculating the difference between said first signal and said film sensitivity output, and an adder for calculating the sum of the first aperture data and the difference calculated in the subtractor to produce a sum output as said second aperture data.

9. The flash photogaphy system according to claim 7, wherein said second aperture data output means comprises a first signal output means for producing a first signal representative of said given film sensitivity, a subtractor for calculating the difference between said first signal and the film sensitivity output, a divider for dividing said difference by a constant value, and an adder for summing said first aperture value data and the result of the division to provide the sum as an aperture control signal.

10. A flash photography system comprising:

(a) first light measuring means for measuring ambient light;

(b) film sensitivity output means for producing a signal representative of the sensitivity of the photographic film used in the camera;

(c) exposure data output means for producing exposure control data for effecting an underexposure of a predetermined amount with respect to a correct exposure value for ambient light photography in response to said first light measuring means and said film sensitivity output means;

(d) exposure control means for controlling the exposure value of the camera based on said exposure control data;

(e) means for effecting flash light emission;

(f) second light measuring means for measuring light reflected from the photographic object from said flash light emission;

(g) means for integrating tle output of said second light measuring means; and

(i) means for stopping the flash light emission when said integrating means reaches a predetermined value.

11. The flash photography, system according to claim 10, further comprising means for producing exposure time data, and said exposure data output means further comprises means for producing a desired aperture value representative of a smaller aperture size by said predetermined value than that for a correct aperture control value for ambient light photography, based on the ambient light value measured by said first light measuring means, the film sensitivity and the exposure time data.

12. The flash photography system according to claim 11, wherein said exposure time data producing means further comprises means for producing manually set exposure time data, fixed exposure data output means for producing fixed exposure time data for flash light photography, and data selecting means for outputting said set exposure time data or said fixed exposure time data.

13. The flash photography system according to claim 10, further comprising means for producing manually set aperture value data, said exposure data output means comprises means for producing exposure time data representative of a shorter exposure time by said predetermined value than that for correct exposure time for ambient light photography, based on the ambient light value measured by said first light measuring means, the film sensitivity and the aperture value data.

14. A flash photography system comprising:

(a) first light measuring means for measuring ambient light;

(b) film sensitivity output means for producing a signal representative of the sensitivity of the photographic film used in the camera;

(c) exposure time signal output means for producing manually set exposure time data;

(d) fixed exposure time output means for producing fixed exposure time data for flash light photography;

(e) data output means for outputting the longer one of said exposure times respectively corresponding to said manually set exposure time data or said fixed exposure time data;

(f) means for calculating an aperture value based on the film sensitivity, the light value of the ambient light and the output data from said data output means;

(g) shutter control means for controlling the camera shutter based on the output data of said data output means;

(h) aperture control means for controlling the actual diaphragm aperture size of the camera based on the calculation of said calculating means;

(i) means for effecting emission of flash light;

(j) second light measuring means for measuring the light reflected from the photographic object from said flash light emission;

(k) means for integrating the output of said second light measuring means;

(l) means for producing a signal to stop the emission of flash light when the output of said integrating means reaches a predetermined value;

said system further comprising;

(m) means for producing fixed data; and

wherein said calculating means includes means for producing a desired aperture value representative of a smaller aperture size by said fixed data than that for the aperture value with the correct exposure for ambient light photography, based on the ambient light value measured by said first light measuring means, the film sensitivity and the output data of said data output means.

15. The flash photography system according to claim 14 wherein said second light measuring means is positioned to receive light passed through a lens means and the diaphragm aperture and in turn reflected by a film plane.

16. The flash photography system according to claim 14, wherein said fixed data is determined by the sensitivity pattern of the light measuring characteristic of said first light measuring means.

17. A flash photography system, comprising:

(a) first light measuring means for measuring ambient light;

(b) first aperture value output means for producing a first aperture value dependent on said ambient light;

(c) second aperture value output means for producing a second aperture value independent of the ambient light value;

(d) first signal output means for outputting said first aperture value or the second aperture value depending on the output of said light measuring means;

(e) means for designating a first exposure control mode or a second exposure control mode;

(f) data selecting means for producing either the output data of said first signal output means upon receipt of said first exposure control mode signal or said first aperture value of said first aperture value output means upon receipt of said second exposure control mode signal;

(g) aperture control means for controlling the actual diaphragm aperture size of the camera corresponding to the output data of said data selecting means;

(h) means for effecting emission of flash light;

(i) second light measuring means disposed to receive the light emitted from a flash device and passed through the diaphragm aperture and reflected by the film plane;

(j) means for integrating the output of said second light measuring means; and

(k) means for producing a signal to stop the emission of flash light when the output of said integrating means reaches a predetermined value.

18. The flash photographing system according to claim 17, further comprising third aperture value output means for producing a manually set third aperture value, said designating means is also capable of designating a third exposure control mode, and said data selecting means is adapted to produce the output of said third aperture value output means in said third exposure control mode.

19. The flash photography system according to claim 17, wherein said first aperture value output means produces an aperture value representative of a smaller aperture size by a predetermined value than that for the correct aperture value for ambient light photography.

20. The flash photography system according to claim 19, wherein said predetermined value is determined by the sensitivity pattern of said ambient light measuring means.

21. A flash photography system comprising:

(a) first light measuring means for measuring ambient light;

(b) first aperture value output means responsive to said first light measuring means for producing a first aperture value representative of a smaller aperture size by a predetermined value than that for the correct aperture value for ambient light photography;

(c) second aperture value output means for producing a second aperture value independent of the ambient light;

(d) first signal output means for outputting said first aperture value or said second aperture value depending on the output value of said light measuring means;

(e) means for outputting a manually set aperture value;

(f) means for designating a first exposure control mode or a second exposure control mode;

(g) data selecting means for producing either the output data of said first signal output means in said first exposure control mode or the manually set aperture value in said second exposure control mode;

(h) aperture control means for controlling the actual diaphragm size of the camera corresponding to the output data of said data selecting means;

(i) means for effecting emission of flash light;

(j) second light measuring means disposed to receive the light emitted from a flash device and passed through the diaphragm aperture and reflected by the film plane;

(k) means for integrating the output of said second light measuring means; and

(l) means for producing a signal to stop the emission of flash light when the output of said integrating means reaches a predetermined value.

22. The flash photography system according to claim 21, wherein said designating means is also capable of designating a third exposure control mode and said data selecting means produces the first aperture value in said third exposure control mode.

23. The flash photography system according to claim 21, wherein said predetermined value is determined by the sensitivity pattern of said ambient light measuring means.

24. A flash photography system comprising:

(a) first light measuring means for measuring ambient light;

(b) film sensitivity output means for producing a signal representative of the sensitivity of the photographic film used in the camera;

lly set

(c) aperture value output means for producing manually set aperture value data;

(d) first exposure time output means for calculating desired exposure time data based on the outputs of said first light measuring means, said film sensitivity output means and said aperture value output means;

(e) second exposure time output means for producing fixed exposure time data;

(f) data selecting means for outputting the longer one of the exposure times respectively corresponding to said desired exposure time data and said fixed exposure time data;

(g) shutter control means for controlling the exposure time based on the output of said data selecting means;

(h) aperture control means for controlling the actual aperture size of the camera based on the output of said aperture value output means;

(i) means for effecting emission of flash light;

(j) second light measuring means for measuring the flash light emitted to, and reflected from, a photographic object;

(k) means for integrating the output of said second light measuring means; and

(l) means for producing a signal to stop the emission of flash light when the output of said integration means reaches a predetermined value.

25. The flash photography system according to claim 24, further comprising means for producing fixed data, and said first exposure time output means includes means for producing exposure time data representative of a shorter exposure time by the fixed data than that for the correct exposure time for ambient light photography, based on the outputs of said first light measuring means, said film sensitivity output means and said aperture value output means.

26. The flash photography system according to claim 25, wherein said fixed data is determined by the sensitivity pattern of the light measuring characteristic of said first light measuring means.

27. The flash photography system according to claim 26, wherein said second light measuring means is positioned to receive light passed through a lens means and the diaphragm aperture and in turn reflected by the film plane.