Camera system

• US 4,664,496 A
• Filed: 04/28/1986
• Issued: 05/12/1987
• Est. Priority Date: 11/08/1975
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawamura, Masaharu, Murakami, Hiroyashu, Ito, Tadashi, Ito, Fumio, Sakurada, Nobuaki, Shinoda, Nobuhiko
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US06/858,902
• Time in Patent Office: 379 Days
• Field of Search: 354/420, 354/422
• US Class Current: 396/169
• CPC Class Codes: G03B 2217/005 Blur detection
• CPC Class Codes: G03B 7/0805 Setting of priority modes
• CPC Class Codes: G03B 7/087 for control of both exposure time and aperture
• CPC Class Codes: G03B 7/089 for storage of exposure value in mirror reflex cameras
• CPC Class Codes: G03B 7/091 Digital circuits
• 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

Most of the elements constituting this camera system consists of digital circuits, whereby a central processing unit is built in this camera system in such a manner that various kinds of photographic modes are possible without increasing the number of the elements.

Claims

1. A photographic camera for flash photography generated by a flash device, the camera comprising:

(a) first signal producing means for producing a first electrical signal corresponding to an exposure time suitable for flash photography;

(b) shutter release means;

(c) shutter control means responsive to actuation of said shutter release means and functionally connected to said first signal producing means to control an exposure time according to the first electrical signal from said first signal producing means when a charge completion signal is generated by said flash device;

(d) setting means for manually setting a shutter speed;

(e) second signal producing means associated with said setting means and producing a shutter speed signal corresponding to a shutter speed selected by the setting means; and

(f) data control means functionally connected to said first signal producing means and said second signal producing means and which compares said first electrical signal with said shutter speed signal and, when the shutter speed signal represents an exposure time longer than that of the first electrical signal, controls the shutter control means so that the shutter control means controls the exposure time in response to the selected shutter speed signal.

2. A photographic camera according to claim 1, wherein said setting means includes a shutter speed dial mounted on the camera body.

3. A photographic camera according to claim 2, wherein said second signal producing means includes:

(a) timing pulse generating means including a plurality of output terminals for transferring a plurality of timing pulses of phases differing from each other;

(b) a single data output line;

(c) a digital data plate including patterns corresponding to shutter speed selected by said shutter speed dial, each of the patterns of said digital data plate having a plurality of conductive means arranged to denote one of said shutter speed values;

(d) contact means including a plurality of electrical brushes connected to corresponding output terminals of said timing pulse generating means contacting with corresponding conductive means of said digital data plate; and

(e) conductive connection means connected to said single data output line and to the conductive means of said digital data plate to transfer, to said single data output line, output digital signals corresponding to the states of the conductive means of said digital data plate in contact with the brushes.

4. A photographic camera according to claim 1, wherein said data control means includes:

(a) subtracting circuit means connected to said first and second signal producing means for subtracting said shutter speed signal from said first electrical signal.

5. A shutter speed selection circuit of a camera, comprising:

a first signal generating circuit for receiving a totally automatic mode signal and a semi-automatic mode signal from a computer type flash unit and for generating a totally automatic mode signal and semi-automatic mode signal corresponding to each of said signals from the flash unit, and

a second signal generating circuit for generating signals indicating shutter speed synchronized with the flash unit in response to the totally automatic mode signal from said first signal generating circuit and at the same time for generating signals corresponding to a shutter speed being manually set in response to the semi-automatic mode signal.

6. A photographic camera usable with an electronic flash unit, comprising:

(a) first signal producing means for producing a semi-automatic mode signal in response to a signal supplied from an electronic flash unit;

(b) second signal producing means for producing a signal representative of a shutter speed synchronized with the flash unit;

(c) third signal producing means for producing a signal corresponding to a shutter speed being manually set;

(d) comparison means for comparing the signal produced by said second signal producing means with the signal from the third signal producing means in response to the semi-automatic mode signal;

(e) fourth signal producing means for producing the signal corresponding to a shutter speed being manually set when the shutter speed manually set is lower than the shutter speed synchronized with the flash unit and producing the signal representative of the shutter speed synchronized with the flash unit when the shutter speed being manually set is higher than the shutter speed synchronized with the flash unit, in response to the output of said comparison means; and

(f) shutter speed control means for controlling the shutter opening time in response to the output from said fourth signal producing means.

7. A photographic camera comprising:

(a) first generating means for generating a signal for a semi-automatic flash photographic mode;

(b) computation order generating means for successively generating orders to perform the semi-automatic flash photographic mode in response to the signal for semi-automatic flash photographic mode;

(c) second generating means for generating digital data corresponding to a shutter speed synchronized to the flash;

(d) third generating means for generating digital data of a manual shutter speed corresponding to a manually set shutter speed;

(e) comparison means for comparing the digital data generated from said second generating means in response to the orders from said computation order generating means with the digital data from said third generating means;

(f) fourth generating means for generating the digital data of the manual shutter speed in response to the order from said computation order generating means when the manually set shutter speed is slower than the flash synchronized shutter speed and for generating digital data corresponding to the flash synchronized shutter speed when the manually set shutter speed is higher than the flash synchronized shutter speed; and

(g) shutter speed control means for controlling a shutter opening time in response to the output from the fourth generating means.

8. A photographic camera comprising:

(a) first generating means for generating a signal for a semi-automatic flash photographic mode;

(b) computation order generating means for successively generating orders to perform the semi-automatic flash photographic mode in response to the signal for semi-automatic flash phtographic mode;

(c) second generating means for generating digital data corresponding to a shutter speed synchronized to the flash;

(d) third generating means for generating digital data of a manual shutter speed corresponding to a manually set shutter speed;

(e) comparison means for comparing the digital data generated from said second generating means in response to the orders from said computation order generating means with the digital data from said third generating means;

(f) fourth generating means for generating the digital data of the manual shutter speed in response to the order from said computation order generating means when the manually set shutter speed is slower than the flash synchronized shutter speed and for generating digital data corresponding to the flash synchronized shutter speed when the manually set shutter speed is higher than the flash synchronized shutter speed; and

(g) indicating means for indicating the output data from the fourth generating means.

9. A photographic camera according to claim 8, wherein said indicating means includes a numeric digital indicating member.