# US 4,397,533 A · Photographic light measuring device

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- Number: US 4,397,533 A
- Document ID: US4397533A
- Status: Granted
- Kind: A
- Application number: 06/315,135
- Filed: 1981-10-26
- Granted: 1983-08-09
- Earliest claimed: 1979-11-20
- Assignees: Minolta Camera Kabushiki Kaisha
- Inventors: Kazuhiko Naruse; Yoshio Yuasa; Norio Ishikawa
- Web page: https://patentgrep.com/patent/US4397533A

## CPC

- G03B 17/18: Signals indicating condition of a camera member or suitability of light (indicating depth of field G03B13/30)
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

In a photographic light measuring device, a light output signal representing light reflected from an object to be photographed is converted into digital signals. At least first and second setting means generate respective first and second digital set signals which are respectively variable in response to respective manual operations. Photographic exposure data signals are generated using the digital light signal and the first and second set digital signals such that indicating means can selectively indicate data commensurate with the first and second digital set signals.

## Claims

### Claim 1

A photographic light measuring device comprising:
means for detecting light of an object and generating an output signal as a function thereof;
A-D converter means for converting said output signal into a digital signal;
a first setting means for generating a first digital set signal representative of first manually set data;
a second setting means for generating a second digital set signal representative of second manually set data;
varying means for selectively controlling said first and second setting means for varying said first and second digital set signals in response to a manual operation;
calculation means for calculating with said digital signal from said A-D converter means, said first set digital signal and said second set digital signal, and generating a calculation output signal as a result of the calculation;
a first indication means for indicating data commensurate with said calculation output signal;
a second indication means for selectively indicating either one of the data commensurate with said first and second digital set signals; and
selection means for selecting the data to be indicated by said second indicating means.

### Claim 2 (depends on 1)

A photographic light measuring device as in claim 1 wherein the signals generated by said control means prevents said first and second setting means from varying said first said second digital set signals when said second indication means does not indicate either of them.

### Claim 3 (depends on 1)

A photographic light measuring device as in claim 1 further comprising timing controller means for preventing the operation of said A-D converter means when said selection means selects said first or second digital set signal to be indicated by said second indication means.

### Claim 4

A photographic light measuring device comprising:
means for detecting light from an object and generating plural kinds of exposure signals as a function of light measurements;
A-D converter means for converting said exposure signals into digital signals;
setting means for selectively generating digital set signals representing different photographic parameters;
means for changing said digital set signals in response to a manual operation;
operational means for selectively making different calculations using said digital signals from said A-D conversion means and said digital set signals, and generating a calculated output signal as a result of the executed calculation;
a first selection means for selecting, in response to a manual operation, the calculation to be executed by said operational means;
indication means for selectively indicating the data commensurate with said digital set signals and said calculated output signal, said first selection means being coupled with said indication means such that the latter indicates the calculated output signal with said first selection means selecting any calculation;
second selection means for enabling indication of selected data commensurate with said digital set signals in place of the indication of the data commensurate with said calculated output signal; and
timing controller means for preventing change of said digital set signals when the data commensurate with the calculated output is indicated.

### Claim 5 (depends on 1)

A photographic light measuring device as in claim 1 wherein said selection means includes control means for generating signals to condition said first and second setting means to respond to said varying means.

### Claim 6 (depends on 5)

A photographic light measuring device as in claim 5 wherein said varying means includes a common varying signal generator for generating varying signals and said first and second setting means are selectively responsive thereto in accordance with said signals generated by said control means.