Camera system

• US 4,304,472 A
• Filed: 11/01/1976
• Issued: 12/08/1981
• 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: Ito, Tadashi, Ito, Fumio, Sakurada, Nobuaki, Shinoda, Nobuhiko, Murakami, Hiroyashu, Kamamura, Masaharu
• Primary Examiner(s): Gellner, Michael L.
• Application Number:
  US05/737,771
• Time in Patent Office: 1,863 Days
• Field of Search: 354/23 D, 354/50, 354/51, 354/60 R, 354/60 A, 354/289, 307/244, 328/153
• US Class Current: 396/292
• 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

In the disclosed photographic exposure control system, an exposure mechanism generates at least one controllable exposure parameter for regulating the exposure of a photosensitive material. A coding circuit is set to produce digital signals corresponding to at least one photographic value. A control device between the coding circuit and the exposure mechanism calculates the exposure parameter and controls the coding circuit. The coded values are then suitably displayed to the photographer.

Claims

1. A digital exposure parameter indicating device for a camera comprising:

(a) a digital signal source for generating a digital data signal corresponding to the digital exposure parameter in the form of a binary number;

(b) first means for generating a signal representing the lowest step of the exposure parameter;

(c) adder circuit means connected to said digital signal souce and to said first means for adding the signal from the first means representing the lowest step of the exposure parameter to a first bit of the digital data signal;

(d) a decoder connected to the adder circuit means for converting a binary number composed of bits from an order next to the first bit to a most significant bit of the added digital data signal into a decimal number; and

(e) indicating means connected to said decoder for indicating the digital exposure parameter as a decimal number in response to the output signal of said decoder.

2. A digital exposure parameter indicating device according to claim 1, wherein said digital signal source includes:

(a) timing pulse generating means which produces a plurality of timing pulses in sequence;

(b) a single data output line;

(c) a digital data plate provided with a pattern composed of a plurality of conductive marks which represent the exposure parameter;

(d) scanning means coupled to said pulse generating means and said plate for receiving said timing pulses and scanning the marks of said digital data plate one after another in synchronism with each timing pulse;

(e) means coupled to said scanning means for supplying the output digital signals of said scanning means corresponding to the states of said marks one after another to said single data output line;

(f) light sensitive means for producing an electrical signal corresponding to the brightness of an object to be photographed;

(g) analog-to-digital converter means connected to said light sensitive means for producing a digital signal in the form of a binary number corresponding to the electrical signal from the light sensitive means; and

(h) calculating means coupled to the converter means and said output line for producing a digital signal in the form of a binary number corresponding to a digital signal from said single data output line representing a binary number and to the digital signal from said analog-to-digital coverter.