GB2122361A

GB2122361A - Shutter-delay antivibration apparatus for reflex cameras

Info

Publication number: GB2122361A
Application number: GB08316041A
Authority: GB
Inventors: Dr George Nyman
Original assignee: C Reichert Optische Werke AG
Current assignee: C Reichert Optische Werke AG
Priority date: 1982-06-18
Filing date: 1983-06-13
Publication date: 1984-01-11
Also published as: JPS59111629A; DE3222925C1; ATA220083A; FR2532073A1; GB2122361B; AT380109B; CA1198923A; GB8316041D0

Abstract

Antivibration apparatus for a reflex camera includes a time-delay device in order to facilitate a time delay between the displacement of a mirror of the camera, and opening of a shutter of the camera. Vibration due to the movement of the mirror is avoided on opening of the shutter. The camera and antivibration apparatus may be formed as an integral unit or alternatively as separate units. Integrated circuit IC3 controls the displacement of the mirror, IC6 is for starting the shutter delay, the period being controlled by variable resistor P1 and capacitor C3. IC13, variable resistor P2 and capacitor C4 control the length of exposure. <IMAGE>

Description

SPECIFICATION Antivibration apparatus for cameras This invention relates to an antivibration apparatus for cameras.

In cameras a mirror may be used to view an image and the mirror can be displaced immediately prior to the exposure of the film. If the mirror forms an integral part of the camera then the camera is generally known as a reflex camera. The displacement of the mirror generates vibrations which can cause blurring of the image. This problem exists, in particular, in microphotography and telephotography.

In the case of microphotography, vibrations tend to be conducted into the region of the objective and the object, so that the vibration is multiplied, on the photograph, by an amount corresponding to the overall magnification of the photo-micrograph. In the case of telephotography, the vibration is amplified in proportion to the focal length of the lens of the camera.

Special-purpose reflex cameras are known, in which the mirror can be displaced, prior to the exposure, by manually-operated electromagnetic or mechanical means. Arrangements for the timed coupling of these means to the shutter are not provided in the case of these cameras.

An object of the present invention is to provide an antivibration apparatus in combination with a camera which is easy to operate, and which enables the sharpness of the image to be relatively unaffected by the vibrations occurring during the displacement of the mirror.

According to one aspect of the present invention there is provided a photographic device comprising a camera, a movable reflex mirror, a shutter, and a time-delay means for generating a delay period between displacement of the mirror and release of the shutter.

Accordihg to another aspect of the present invention there ks provided an antivibration apparatus for a camera including means for actuating displacement of a mirror of the camera, means for actuating opening of a shutter of the camera, and a time-delay device for generating a delay period within the range of 0.2 seconds to 1 second, between displacement of the mirror! and opening of the shutter.

Preferably the camera is a reflex camera and the mirror forms an integral part of the camera.

The delay can advantageously be provided by means of a one-shot multivibrator. The delay enables the vibrations caused by the displacement of the mirrorito die away before the shutter opens.

Preferably the delay is within the range of 0.3 seconds t 0.5 seconds.

The delay period preferably can be adjusted in an infinitely variable manner, so that it can be accurately set to the optimum value for the particular conditions under which the exposure is to be made.

In one embodiment the antivibration apparatus and the camera may form an integral unit which can be provided with a switch for switching the antivibration apparatus on and off. When the switch is off the camera may be operated with no delay, or a delay of much less than 0.2 seconds, to enable normal photography to be performed.

In an alternative embodiment the antivibration apparatus and the camera form separate units, said antivibration apparatus further including a starting key adapted to trigger the time-delay device, a first lead adapted to be connected to the starting key and to the shutter, and a second lead adapted to be connection to an output terminal of the time-delay device and to the shutter.

In a further embodiment the antivibration apparatus and the camera form separate units, the camera further including a terminal for actuating displacement of the mirror and the antivibration apparatus further including a starting key adapted to trigger the time-delay device, a first lead adapted to be connected to the starting key and to the camera terminal, and a second lead adapted to be connected to the output terminal of the time-delay device and to the shutter.

The camera may include an accessory unit, and the shutter can form part of the accessory unit, This arrangement is preferably used in microscopy applications.

In the embodiments in which the camera and the antivibration apparatus are separate units the reflex camera can be set to the setting in which the exposure time is of any desired length. On commercial reflex cameras this is known as the 'B' setting.

The sequence of operations in the course of exposure is determined by the antivibration apparatus.

The camera may be provided with a common terminal for both the displacement of the mirror and opening of the shutter. When employing this arrangement the camera may be operated with no delay, or a delay much less than 0.2 seconds, thus enabling normal photography to be performed; after the shutter has closed the mirror swings back without delay.

The camera may be provided with a terminal for displacement of the mirror and a separate terminal for opening the shutter. The shutter may form an integral part of the camera or may be provided in a microscopy instrument. When employing this arrangement the shutter opens after the mirror has been displaced when the delay period set by the time-delay device has expired.

Reference is now made to the accompanying drawing which illustrates an electric circuit diagram for an antivibration apparatus according to the invention.

The drawing shows a circuit diagram for an antivibration apparatus which may be provided as an integral part of camera, or as a unit separate from the camera.

The circuit uses three main integrated circuit units designated IC3, IC6 and IC13, for which a reset power impulse is provided by resistor R3 and capacitor C2 in conjunction with a 12 volt power supply. Integrated circuits IC3, IC6 and IC13 may be reset by switching the "stop" switch on.

The circuit is provided with a first lead which can be connected to a terminal for actuating displacement of the mirror. In the embodiment in which the antivibration apparatus forms a unit separate from the camera, the first lead may be connected to a common terminal for actuating displacement of the mirror, and opening of the shutter.

A second lead is provided which can be connected to a terminal provided for the shutter. The shutter may be provided on the camera or on an extension in, for example, a microscopy instrument.

Integrated circuit 103 is a bistable flip-flop which can change the condition of the first lead from "off" to "on" in order to actuate displacement of the mirror. Integrated circuit IC6 is a mono flip-flop for starting the shutter display time, and IC13 is a mono flip-flop which controls the opening of the shutter, and the length of the exposure time.

A delay on/off switch is provided so that the delay period, which is generated by integral circuit IC6, can be switched off.

Exposure may be initiated by pressing the start switch. immediately the start switch is pressed "on", the output condition of integrated circuit IC3 is changed from "off" to "on" thereby actuating the displacement of the mirror through the first lead.

If the delay on/off switch is "off", the output of integrated circuit IC13 changes from "off" to "on" immediately after the output of integrated circuit IC3 has changed from "off" to "on", thereby opening the shutter without any substantial delay.

If the delay on/off switch is "on", the integrated circuit IC13 changes from "off" to "on" after the expiry of a delay period generated by integrated circuit IC6, thereby opening the shutter after the displacement of the mirror when the delay period set by integrated circuit IC6 has expired.

After the exposure is complete integrated circuit IC3 is reset via output Q of integrated circuit IC13 and through integrated circuits IC4 and IC2, thereby returning the mirror to its original position.

Variable resistor P1 and capacitor C3 control the delay period provided by integrated circuit IC6.

Variable resistor P2 and capacitor C4 control the exposure time provided by integrated circuit It13.

Claims

1. A photographic device comprising a camera, a movable reflex mirror, a shutter, and a time-delay means for generating a delay period between displacement of the mirror and release of the shutter.

2. The photographic device of Claim 1 wherein the delay period is from about 0.2 seconds to about 1 second.

3. The photographic device according to Claim 1 wherein the camera is a reflex camera, and the mirror forms an integral part of said camera.

4. The photographic device according to Claim 1 wherein said camera is attached to a microscope and the shutter is between said camera and the microscope.

5. A photographic device according to Claim 1 in which the delay period can be adjusted in an infinitely variable manner.

6. A photographic device according to Claim 1 in which the antivibration apparatus and the camera form an integral unit, further including a switch to activate and deactivate said time delay means.

7. A photographic device according to Claim 1 in which the time delay means and the camera are separate units, said time delay means further including a start switch adapted to trigger the time-delay device, a first lead adapted to be connected to the starting key and to the shutter, and a second lead adapted to be connected to an output terminal of the time-delay device and to the shutter.

8. A camera according to Claim 6 which includes an accessory unit, and the shutter forms part of the accessory unit.

9. A camera according to Claim 1 in which the antivibration apparatus and the camera form separate units, the camera further including a terminal for actuating displacement of the mirror, and the antivibration apparatus further including a starting key adapted to trigger the time-delay device, a first lead adapted to be connected to the starting key and to the camera terminal, and a second lead adapted to be connected to the output terminal of the timedelay device and to the shutter.

10. A camera according to Claim 8 which includes an accessory unit, and the shutter forms part of the accessory unit.

11. An antivibration apparatus for a camera including means for actuating displacement of a mirror of the camera, means for actuating opening of a shutter of the camera, and a time-delay device for generating a delay period within the range of 0.2 seconds to 1 second between displacement of the mirror and opening ofthe shutter.

12. A method of avoiding the effect of vibration of a movable mirror on a photograph which comprises the steps of a. actuating a release mechanism, b. moving a mirror out of the photographic optical system in response to actuation of said release mechanism, c. actuating a time delay means in response to activation of said release mechanism, and d. actuating a shutter means in response to a signal from said time delay means, whereby said shutter is actuated after said mirror stops vibrating.

13. A photographic device substantially as herein described with reference to and as shown in the accompanying drawings.

14. A method according to Claim 12 substantially as herein described with reference to and as shown in the accompanying drawings.