Focal plane shutter camera having an electromagnetic diaphragm mechanism

• US 4,167,313 A
• Filed: 12/05/1977
• Issued: 09/11/1979
• Est. Priority Date: 12/29/1976
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Tsunefuji, Katsuhiko
• Primary Examiner(s): Hix, L. T.
• Assistant Examiner(s): Perkey, Willliam B.
• Application Number:
  US05/857,249
• Time in Patent Office: 645 Days
• Field of Search: 354/29-31, 354/36, 354/38, 354/40, 354/43, 354/44, 354/46, 354/50, 354/51, 354/60 R, 354/60 L, 354/228, 354/234, 354/271, 354/273, 352/141
• US Class Current: 396/233
• CPC Class Codes: G03B 7/085 for control of aperture

Abstract

A focal plane shutter camera of a type which employs photometry measuring light reflected by the shutter blind and/or the film has an electromagnetic diaphragm mechanism and is capable of automatic photographing with a preset exposure. By providing at least two light receiving elements which perform the photometry of reflected light to automatically determine an exposure value, the camera may select among four photographing modes including a manual photographing, an automatic photographing with a preset diaphragm aperture, an automatic photographing with a preset exposure period and an automatic programmed photographing operation.

Claims

1. A focal plane shutter camera of the type including a focal plane shutter comprising a first blind and a second blind and in which photometry is made of light from an object being photographed which passes through a taking lens and a diaphragm and into the camera and which is reflected by at least one of the surfaces including the shutter blind and a film surface;

the camera comprising a light receiving element for receiving light from an object being photographed which passes through the taking lens into the camera and which is reflected by at least one of the surfaces including the shutter blind and the film surface;

a first shutter blind drive mechanism and a second shutter blind drive mechanism each operative to permit a running of the first blind and the second blind, respectively, for opening and closing the shutter;

an electromagnetic diaphragm mechanism assembled into the lens barrel of the taking lens for electromagnetically opening and closing the diaphragm;

a manual exposure period control circuit for permitting a manual setting of the exposure period externally of the camera;

an automatic diaphragm aperture control circuit including the light receiving element for outputting a diaphragm control signal in accordance with the brightness of an object being photographed, and responsive to an output from the manual exposure period control circuit;

a drive circuit responsive to an output from the automatic diaphragm aperture control circuit for driving the electromagnetic diaphragm mechanism;

a first shutter blind run control circuit responsive to an output of the automatic diaphragm aperture control circuit for operating the first blind drive mechanism; and

a second shutter blind run control circuit responsive to an output of the manual exposure period control circuits for operating the second blind drive mechanism;

the camera being capable of automatic photographing with a preset exposure period.

2. A focal plane shutter camera according to claim 1 in which the first blind run control circuit comprises a pair of comparators responsive to an output of the automatic diaphragm aperture control circuit, and a pair of switching transistors connected to receive the output of each comparator and forming an AND circuit, the AND circuit being enabled to permit a shutter operation only when a proper diaphragm aperture is formed.

3. A focal plane shutter camera according to claim 2 in which the inputs of the AND circuit are connected with light emitting elements which provide an indication of an improper exposure visible within the viewfinder of the camera.

4. A focal plane shutter camera of the type including a focal plane shutter comprising a first blind and a second blind and in which photometry is made of light from an object being photographed which passes through a taking lens and a diaphragm into the camera and which is reflected by at least one of the surface of the shutter blind and a film surface;

the camera comprising a first and a second light receiving element for receiving light from an object being photographed which passes through the taking lens into the camera and which is reflected by at least one of the surfaces including the shutter blind and the film surface;

a first shutter blind drive mechanism and a second shutter blind drive mechanism each operative to permit a running of the first blind and the second blind, respectively, for opening and closing the shutter;

an electromagnetic diaphragm mechanism assembled into the lens barrel of the taking lens for electromagnetically opening and closing the diaphragm and a manual diaphragm member associated with the mechanism;

a manual exposure period control circuit for permitting a manual setting of the exposure period externally of the camera;

an automatic diaphragm aperture control circuit including the first light receiving element for outputting a diaphragm control signal in accordance with the brightness of an object being photographed, and responsive to an output from the manual exposure period control circuit;

a drive circuit selectively responsive to an output from the automatic diaphragm aperture control circuit and a setting by a manual diaphragm member for driving the electromagnetic diaphragm mechanism;

a first shutter blind run control circuit responsive to an output of the drive circuit for operating the first blind drive mechanism;

an automatic exposure period control circuit including the second light receiving element for outputting an exposure period control signal in accordance with the brightness of an object being photographed;

a second shutter blind run control circuit selectively responsive to an output of the automatic and manual exposure period control circuits for operating the second blind drive mechanism; and

a switching device for changing the interconnection between the circuits to permit a selection among photographing modes including a manual photographing, an automatic photographing with a preset exposure period, an automatic photographing with a preset diaphragm aperture and an automatic, programmed photographing operation.

5. A focal plane shutter camera of the type including a focal plane shutter comprising a first blind and a second blind in which photometry is made of light from an object being photographed which passes through a taking lens and a diaphragm and into the camera and which is reflected by at least one of the surfaces including the shutter blind and a film surface;

the camera comprising a light receiving element for receiving light from an object being photographed which passes through the taking lens and into the camera and which is reflected by at least one of the surfaces including the shutter blind and the film surface;

a first shutter blind drive mechanism and a second shutter blind drive mechanism each operative to permit a running of the first blind and the second blind, respectively, for opening and closing the shutter;

an electromagnetic diaphragm mechanism assembled into the lens barrel of the taking lens for electromagnetically opening and closing the diaphragm;

resistors selected by a given programmed condition;

an automatic diaphragm aperture control signal responsive to an output of a photometry circuit including the resistors and the light receiving elements;

a drive circuit responsive to an output of the automatic diaphragm aperture control circuit for driving the electromagnetic diaphragm mechanism;

a first shutter blind run control circuit responsive to an output of the automatic diaphragm aperture control circuit for operating the first blind drive mechanism;

a light receiving element for receiving light from an object being photographed which passes through the diaphragm which is opened to a given aperture value by the diaphragm mechanism drive circuit and reflected by the surface of the shutter blind or by the film surface;

a second shutter blind run control circuit including the light receiving element which circuit initiates a time count operation in synchronism with the initiation of the first shutter blind run and operates the second shutter blind drive mechanism;

the camera being capable of an automatic programmed photographing and having a reflex photometry system.

6. A focal plane shutter camera according to claim 5 further including a negative feedback circuit including a plurality of programmed condition changing resistors connected between the output terminal and the input terminal of the automatic diaphragm aperture control circuit, one of the resistors being chosen to establish a desired condition during the programmed photographing operation.

7. A focal plane shutter camera according to claim 5 in which the first blind run control circuit comprises a pair of comparators responsive to an output of the automatic diaphragm aperture control circuit, and a pair of switching transistors connected to receive the output of each comparator and forming an AND circuit, the AND circuit being enabled to permit a shutter operation only when a proper diaphragm aperture is formed.

8. A focal plane shutter camera according to claim 7 in which the inputs of the AND circuit are connected with light emitting elements which provide an indication of an improper exposure visible within the viewfinder of the camera.