Alarm device for camera

• US 4,688,921 A
• Filed: 08/08/1986
• Issued: 08/25/1987
• Est. Priority Date: 08/13/1985
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nippon Kogaku K. K. (Nikon Corporation)
• Inventors: Wakabayashi, Tsutomu
• Primary Examiner(s): Adams, Russell E.
• Application Number:
  US06/894,959
• Time in Patent Office: 382 Days
• Field of Search: 354/441, 354/442, 354/443, 354/444, 354/445, 354/412, 354/416, 354/417, 354/145.1, 354/127.1, 354/127.11, 354/127.12, 354/471, 354/473, 354/474, 354/475 , 354/286, 354/289.1, 354/289.11, 354/289.12, 354/21
• US Class Current: 396/170
• CPC Class Codes: G03B 17/18 Signals indicating condition of a camera member or suitability of light indicating depth of field G03B13/30

Abstract

An alarm device for a camera provided with a stop control device for automatically controlling the stop of an objective lens mounted on the camera, and a photosensor for receiving an illumination light which has been radiated from a flash device to be electrically connected to the camera, reflected from an object and passed through the stop, the output of the photosensor being used for control of the light emission quantity of the flash device, includes: a lens discriminating unit for discriminating the type of the objective lens and outputting a first signal when an objective lens not suitable for an automatic stop control by the stop control device is mounted on the camera; a flash device detecting unit for generating a second signal upon detecting that the flash device is electrically connected to the camera and a flash light is permitted to be radiated; a judging unit including a unit for presetting a stop value of the objective lens and a unit for setting beforehand a limit stop value for a flash photography, the judging unit generating a third signal when the preset stop value exceeds the limit stop value; and an alarm unit for giving an alarm signal when the first, second and third signals are all generated.

Claims

1. An alarm device for a camera provided with a stop control device for automatically controlling the stop of an objective lens mounted on the camera, and a photosensor for receiving an illumination light which has been radiated from a flash device electrically connected to the camera, reflected from an object and passed through the stop, the output of the photosensor being used for control of the light emission quantity of the flash device, comprising:

lens discriminating means for discriminating the type of said objective lens and outputting a first signal when an objective lens not suitable for an automatic stop control by said stop control device is mounted on the camera;

flash device detecting means for generating a second signal upon detecting that said flash device is electrically connected to the camera and a flash light is permitted to be radiated;

judging means including means for presetting a stop value of said objective lens and means for setting beforehand a limit stop value for a flash photography, said judging means generating a third signal when said preset stop value exceeds said limit stop value; and

alarm means for giving an alarm signal when said first, second and third signals are all generated.

2. An alarm device for a camera according to claim 1, wherein said camera includes means for selecting a mode wherein an exposure is controlled by said stop control device;

said alarm device further includes photographic mode detecting means for generating a fourth signal upon detecting that said mode has been selected by said mode selecting means; and

wherein said alarm means generates said alarm signal when said first, second, third and fourth signals are all generated.

3. An alarm device for a camera according to claim 1, wherein said alarm means includes display means which is driven in response to said alarm signal.

4. An alarm device for a camera according to claim 1, wherein said alarm means includes means for inhibiting taking a photograph with said camera in response to said alarm signal.

5. An alarm device for a camera according to claim 1, wherein said limit stop value setting means sets said limit stop value based on the film sensitivity of a film loaded in said camera.

6. An alarm device for a camera according to claim 1, wherein said limit stop value setting means sets said limit stop value based on the film sensitivity of a film loaded in said camera, and at least one of a distance of an object and a guide number of said flash device.