Display unit for flashlight photography

• US 4,494,851 A
• Filed: 10/25/1982
• Issued: 01/22/1985
• Est. Priority Date: 10/31/1981
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nippon Kotsu Kabushiki Kaisha (Nikon Corporation)
• Inventors: Iida, Yoshikazu, Hasegawa, Hiroshi, Maida, Osamu, Hagyuda, Nobuyoshi
• Primary Examiner(s): Adams, Russell E.
• Assistant Examiner(s): Brown, Brian W.
• Application Number:
  US06/436,430
• Time in Patent Office: 820 Days
• Field of Search: 354/31, 354/32, 354/33, 354/34, 354/60 F, 354/127, 354/128, 354/139, 354/145, 354/149, 354/266, 354/289, 354/421
• US Class Current: 396/163
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/05 Combinations of cameras with electronic flash units
• 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

In a flashlight emission system, apparatus for lighting a flash tube to illuminate an object and for controlling the quantity of emitted light from the flash tube, the apparatus being cooperative with a camera having structure for presetting ASA speed of film and aperture value of a taking lens prior to taking, there is provided a device for displaying the limit of object distance for providing an optimum exposure to the film comprising; apparatus for receiving information of the ASA speed and aperture value from the camera to make up first data corresponding to the received information; apparatus for making second data indicative of the limit of the quantity of emitted light controllable by the control apparatus; a device for calculating the limit of object distance from the first and second data and generating an output corresponding to the limit found out by the calculation; and apparatus for making a visual display of the limit of object distance in response to the output of the calculation device.

Claims

1. In a flashlight emission apparatus having means for lighting a flash tube to illuminate an object to be taken and means for controlling the quantity of emitted light from said flash tube, said apparatus being cooperative with a camera having means for generating preset information of ASA speed value of a film and aperture value of the taking lens prior to taking, the improvement provided with a device for making a display of the limit of object distance for providing an optimum exposure to said film by the emitted light controlled by said control means, the device comprising:

(a) means for receiving said preset information from said camera to provide first data corresponding to the received information;

(b) means for providing second data substantially identical with said first data;

(c) means for providing third data indicative of the limit of the quantity of emitted light controllable by said control means;

(d) selection means for selecting one data from the first data and second data;

(e) means for forming an output corresponding to said limit of object distance from said selected one and third data; and

(f) means for effecting a visual display of said limit of object distance in response to the output of said output forming means.

2. Flash light emission apparatus cooperative with a camera in flashlight phototaking, the camera generating preset information of ASA speed value of a film and aperture value of a taking lens, the apparatus comprising:

(a) means for receiving said preset information from said camera to provide first data corresponding to the received information;

(b) means for providing second data substantially identical with said first data;

(c) selection means for selecting one data from the first data and second data;

(d) means provided with means which generates during the flashlight phototaking a photometering output corresponding to the quantity of light from an object to control the quantity of emitted light from said flashlight emission apparatus in response to said one data selected by said selection means and said photometering output;

(e) means in response to said one data selected by said selection means for forming prior to said flashlight phototaking an output corresponding to the limit of object distance to provide an optimum exposure; and

(f) means for effecting a visual display of said limit of object distance in response to the output of said output forming means.

3. A flashlight emission apparatus as set forth in claim 2 further comprising means for forming a third data indicative of the limit of quantity of the emitted light from said flashlight emission apparatus, wherein said output forming means forms said output in response to said one data and said third data.

4. A flashlight emission apparatus cooperative with a camera in flashlight phototaking, the camera generating preset information of ASA speed value of a film and also generating a first emission stop signal when emitted light from a flash tube reaches a value determined by said preset information, the apparatus comprising:

(a) means for receiving said preset information from said camera to provide first data corresponding to the received information;

(b) means for providing second data substantially identical with said first data;

(c) means provided with means which generates during said flashlight phototaking a photometering output corresponding to the quantity of light from an object to generate a second emission stop signal when said photometering output reaches a value determined by said second data;

(d) selection means for selecting one data from the first data and second data;

(e) means for stopping the light emission in said flash tube in response to said first emission stop signal from said camera when said first data is selected and in response to said second emission stop signal from said generating means when said second data is selected, respectively;

(f) means in response to said one data selected by said selection means for forming prior to said flashlight phototaking an output corresponding to the limit of object distance to provide an optimum exposure; and

(g) means for effecting a visual display of said limit of object distance in response to the output of said output forming means.

5. A flashlight emission apparatus cooperative with a camera in flashlight photographing for controlling a quantity of light emitted from a flash tube which is energized by an electric charge from a main capacitor to provide an optimum exposure in taking an object illuminated by light;

the apparatus comprising;

(a) means for forming a correction output changeable according to the quantity of the electric charge of said main capacitor;

(b) means for detecting the charged voltage on said main capacitor;

(c) means for inputting information relating to ASA speed value and aperture value;

(d) means for producing an operation output corresponding to the limit of object distance for providing an optimum exposure under the quantity of emitted light depending upon the quantity of the electric charge of said main capacitor based on said correction output and said information relating to ASA speed value and aperture value; and

(e) means for effecting a visual display of the limit of object distance in response to the operation output, said display means in response to said detecting means being enabled while the charged voltage of said main capacitor is exceeding a threshold level necessary for lighting said flash tube and being disabled while the charged voltage is not exceeding said threshold level.

6. A flashlight emission apparatus as set forth in claim 5 wherein said correction output forming means includes means for providing a flow of current in magnitude corresponding to the charge voltage of said main capacitor and means for converting said flow of current into a logarithmically compressed voltage.

7. A flashlight emission apparatus cooperative with a camera for flashlight photographing and having an electric circuit for controlling the quantity of emitted light from said flash tube for providing an optimum exposure for taking the object with the flashlight, said apparatus comprising:

(a) means for inputting information relating to ASA speed value and aperture value;

(b) means for forming a first output corresponding to the minimum object distance at which the control of the quantity of the emitted light by said electric circuit is possible for providing the optimum exposure, said first output being formed based on said input information;

(c) means for forming a second output corresponding to a determined minimum object distance at which said object can be illuminated uniformly by said flashlight emission apparatus;

(d) means for selecting one of the first and second outputs which represents a larger distance, and putting out said selected one; and

(e) means for effecting a visual display of said minimum distance in response to the output from said selection means.

8. A flashlight emission apparatus cooperative with a camera for flashlight photographing and controlling the quantity of the light emitted from said flash tube to illuminate an object to be taken in an optimum exposure with the flashlight, said apparatus comprising:

(a) means for inputting information relating to ASA speed value and aperture value;

(b) means for forming a first output corresponding to a determined minimum object distance at which said object can be uniformly illuminated by said flashlight emission apparatus, said first output being formed based on said input information;

(c) means for forming a second output corresponding to the maximum object distance at which the flashlight can be controlled for providing the optimum exposure, said second output being formed based on said input information;

(d) means for making a display of at least one of said minimum distance and maximum distance in response to at least one of said first and second outputs; and

(e) means for comparing said first output with said second output and generating a signal only when said minimum distance is larger than said maximum distance.

9. A flashlight emission apparatus as set forth in claim 8, which further comprises means for providing a warning display in response to said signal.

10. A flashlight emission apparatus as set forth in claim 8, wherein said display means includes means for concelling the display in response to said signal.

11. A flashlight emission apparatus having a flash tube able to emit light to illuminate an object to be taken and means for controlling the quantity of emitted light from said flash tube to provide an optimum exposure for taking the object with the flashlight, and being cooperative with a camera including means for setting a taking distance according to the object distance for the flashlight photographing, said apparatus comprising:

(a) means for inputting information relating to ASA speed value and aperture value;

(b) means for calculating the maximum and minimum object distances at which the emitted light can be controlled for providing the optimum exposure by the flashlight photographing, said calculation being based on said input information;

(c) means for introducing the taking distance set by said setting means into said flashlight emission apparatus from said camera;

(d) first checking means for verifying that said introduced taking distance is between said maximum distance and said minimum distance;

(e) switching means operable to cancel the control of the quantity of emitted light by said control means; and

(f) second checking means responsive to the operation of said switching means for verifying that said introduced taking distance is substantially equal to said maximum distance.

12. A flashlight emission apparatus as set forth in claim 11, which further comprises means for selectively effecting a display of the result given by said first checking means or the result given by said second checking means in response to the operation of said switching means.

13. A flashlight emission apparatus as set forth in claim 12, which further comprises;

capacitor means for storing electric charge to be used for lighting said flash tube;

detection means for continuously generating an output until the storing of the charge in said capacitor means is completed; and

means for cancelling the display of the result given by said second checking means in response to the output of said detection means.

14. A flashlight emission apparatus as set forth in claim 12, which further comprises capacitor means for storing electric charge to be used for lighting said flash tube and means for detecting the voltage on said capacitor means, and wherein said calculating means includes means responsive to said detection means to correct the calculated maximum distance.

15. In a camera cooperative with a flashlight emission apparatus for exposing a photosensitive film to light, the improvement comprising a device for output of information used to control the light-emission from said flashlight emission apparatus, said information output device including:

(a) means for generating first information corresponding to ASA speed value and aperture value set by an ASA film-speed value setting means and aperture value setting means contained in said information generating means;

(b) means for measuring the quantity of light transmitted through a taking lens of the camera during the light-emission from said flashlight emission apparatus and generating second information when the measured quantity of light reaches a determined value;

(c) an electric output terminal for connection with said flashlight emission apparatus;

(d) releasing means operated for starting the exposure of film; and

(e) means for selectively connecting said first and second information generating means with said output terminal, said connecting means selecting said first information before said releasing means is operated and selecting said second information during the time from the operation of said releasing means at least to the completion of the exposure.

16. Apparatus as set forth in claim 15, wherein said flashlight emission apparatus includes:

an input terminal to be connected with said output terminal of the camera;

a flash tube;

means for controlling the quantity of emitted light from said flash tube;

means for forming a signal indicative of the limit of the quantity of emitted light controllable by said control means; and

means for calculating the limit of object distance at which an optimum exposure for said film is obtainable under the control of emitted light by said control means, said calculation being made from said signal and said first information introduced from said input terminal.

17. A camera provided with apparatus for automatically controlling exposure factor in accordance with the brightness of an object to be taken to provide an optimum exposure for photographing without flashlight, which camera can be used also for flashlight photographing when it is connected with a flashlight emission apparatus having a flash tube able to emit light to illuminate the object and means for controlling the quantity of emitted light from said flash tube so as to provide as optimum exposure, said camera comprising:

(a) first means for generating first information relating to the exposure factor to be controlled by said control apparatus for photographing without flashlight;

(b) second means for generating second information relating to the limit of object distance at which the control of the quantity of emitted light by said control means of said flashlight emission apparatus is possible to obtain the optimum exposure; and

(c) display means having a display member which can be driven selectively in a first mode to make a visual display of said exposure factor and in a second mode to make a visual display of said limit of object distance, said display means driving said display member in the first mode in response to said first information and in the second mode in response to said second information.

18. A camera as set forth in claim 17, wherein said flashlight emission apparatus includes means for calculating said limit of object distance and wherein said second means is connected with said calculating means by connecting said flashlight emission apparatus with said camera and generates information of the calculated limit of object distance as said second information.

19. A camera as set forth in claim 18, wherein said calculating means of said flashlight emission apparatus includes means for generating a series of pulse signals having a period corresponding to said limit of object distance.

20. A camera as set forth in claim 19, wherein said flashlight emission apparatus includes capacitor means for accumulating the electric charge to be used to cause said flash tube to emit light, means for producing a detection signal in response to the accumulation of the electric charge in the capacitor means, and transmission means having an output terminal and adapted to apply to said output terminal said series of pulse signals with said detection signal superimposed thereon, and wherein said camera includes a terminal to be connected with said output terminal of said transmission means.