WO1981000464A1

WO1981000464A1 - Process and device for taking photographic pictures of moving objects

Info

Publication number: WO1981000464A1
Application number: PCT/EP1980/000070
Authority: WO
Inventors: O Hahn; H Sittenauer
Original assignee: Schwenk D
Priority date: 1979-08-02
Filing date: 1980-08-01
Publication date: 1981-02-19
Also published as: EP0040196A1; DE3049775D2; EP0040196B1; DE2931408A1; GB2080558A; GB2080558B

Abstract

The process and device for taking pictures of moving objects are provided to allow the use of conventional photographic apparatuses and lenses. For that purpose, a photographic apparatus is used having two shutters arranged one behind the other. The release action in the apparatus causes first the opening of the first shutter. Within the interval of said opening, the opening of the second shutter is controlled by the contact of the flash of the photographic apparatus. During the opening of the second shutter, the emission of the flash pulse is released also through the contact of the flash of the apparatus. Hence, all the power of the flash is used for taking a picture. The arming mechanism provided for the device allows a particularly high sequence of shots.

Description

Method and device for producing photographic images of moving objects

The invention relates to a method for producing photographic recordings of moving objects, in which the object is illuminated with flash light and the illuminated object is photographed with an Eamera synchronized with the flash light, which has two closures connected in series.

The invention further relates to a corresponding device with a camera, with a first shutter built into the camera, with a second shutter connected in front of the camera, which can be opened for camera adjustment independently of the camera release, and with a flash device connected to the camera, wherein when the camera is triggered, the first shutter is opened and the second shutter is opened to expose the film. There are two main types of shutter known for cameras, namely slot locks and central locks. The slit closure consists of two curtains with a slit opening in which the blinds run horizontally or vertically during exposure with the slit open. The shortness of the exposure time depends on the slot width, since the blinds are moved at a constant speed.

With slit shutters, very short exposure times of up to about 1/2000 seconds can be achieved, with the roller blinds being located close to the film in the camera housing. This has the advantage that the camera window remains free and practically all interchangeable lenses and fancy optical systems can be used without the need for a new shutter each time.

While short exposure times of less than 1/125 seconds eliminate the problem of camera shake with the slit shutter, another problem occurs with such and shorter exposure times if you want to work with electron flash lighting. Experience has shown that the slit shutter can only be synchronized for exposure times from 1/30 seconds to a maximum of 1/125 seconds, so that when taking flash pictures with a shorter exposure time, the flash light only comes into effect partially when the shutter is open.

With central locks you can work with flash sync up to shutter speeds of 1/500 seconds, but in this palle the difficulty arises that the central lock in general is arranged where the beam has a minimal diameter so that the central shutter does not perform an aperture function. In practice, this means that the central shutter is generally permanently installed in the camera lens, possibly behind the rear lens in the camera housing. In this way, the central shutter is never arranged directly in front of the film, and due to the fact that the rear lens is also part of the lens system with interchangeable lenses, you are dependent on the interchangeable lenses offered by the respective camera manufacturer and limited in terms of the possible focal length range.

From DE-OS 2045 707 a single-lens reflex camera with two closures connected in series is already known, in which a control device is to ensure that the opening and closing processes of the two closures for focusing by the viewfinder and exposure take place in exact time sequence. The arrangement described there works with a control circuit with first and second switches connected to an electromagnet, which interact with complex mechanics to mechanically control the opening and closing of the two closures depending on certain conditions. The mechanically operated switches are arranged in the camera housing and connected to an operating mechanism in the lens barrel.

In the device specified there, however, a lens with a built-in central shutter can only be expediently used in conjunction with the matching Eamera. Comments on how A flash synchronization with the two provided closures should not be found in the document mentioned.

The invention is therefore based on the object of specifying a method and a device which enable the user to work independently of certain lens systems for the production of photographic recordings of rapidly moving objects brightened by flash light and to use cameras and single-lens reflex cameras from any manufacturer without restriction of the focal length.

The solution according to the invention consists in first opening a slotted shutter built into the camera housing as the first shutter in a method of the type specified when the camera is triggered, controlling the opening of the second shutter designed as a central shutter from the first shutter of the camera via its lightning contact, and triggering to control the flash light from the second shutter via its flash contact, so that the entire flash light interval lies in the opening interval of the second shutter and this is completely in the opening interval of the first shutter.

With the method according to the invention it is advantageously achieved that the risk of overexposure is reduced considerably in the case of strongly illuminated objects, so that the method can be used both during the day and at night. In this case, use can advantageously be made of the effect that the brightening during the day by means of flashing light is better, the larger the aperture and the faster the shutter speed is, since those who work with very short flash-synchronized shutter speeds that can. These short shutter speeds, in turn, offer the advantage that there are no motion blurs when objects are moving particularly quickly.

If one works in the method according to the invention with interleaved time intervals which are of the order of magnitude 1/15 seconds for the first shutter, 1/500 seconds for the second shutter and 1/1000 seconds for the flash light, this advantageously achieves that on the one hand no difficulties occur with the flash synchronization, while on the other hand fast moving objects can be recorded without motion blur.

The device according to the invention is characterized in that the second shutter is designed as a central shutter, which is installed in the lens barrel in front of or in the camera lens and is connected to the flash contact of the camera, so that when the camera is triggered, the shutter speed is considerably shorter than the first one Closure is opened by the flash contact, and that the central lock is in turn connected to the flash contact of the flash unit and controls the delivery of the flash pulses "within the opening intervals of the two locks.

The device according to the invention ensures that there is no overlap of the individual opening intervals, so that the entire flash output can be used in the photographic recordings. The user is completely free to choose the respective Eamera, the lenses and focal lengths to be used as well as the camera manufacturer and can still take advantage of modern SLR cameras with built-in slit locks. A major advantage of the device according to the invention can be seen in the fact that lenses with a built-in central shutter with corresponding adapter rings can be easily adapted to any camera with interchangeable optics and slit shutter and can be operated without any further conversion measures . B. Leica cameras can also be used. The time-synchronized sequence of the two shutters is controlled by the normal and already existing flash contact on the camera, while the flash light is triggered by the flash contact of the central shutter in the lens barrel. Instead of the lightning contact on the camera, for example, another existing additional contact on the camera, e.g. B. for exposure through a so-called data back wall, or a contact for a second camera.

The camera can be set with a view through the viewfinder in such a way that the lens shutter is opened manually and closed again after the setting has been made, so that the lens shutter is closed when the camera is triggered. Such handling is suitable for many purposes, especially when shooting from a fixed position. In areas of application that require a view through the viewfinder until just before the release, an additional element that is independent of the camera can be easily attached to the camera release, which ensures that the lens shutter closes automatically when the release is started, during the brief opening of the lens shutter for the exposure of the film is triggered by the flash contact of the camera. The lens shutter, designed as a central shutter, can of course also be switched in such a way that it optionally remains fully open and the actual exposure of the film in the camera is then exclusively dependent on the slit shutter in the camera housing itself. This can prove to be particularly useful when lighting with a flash is not required and the short exposure times of slot closures should come into play.

In one embodiment of the device according to the invention, the actuating device of the central lock has a trigger, an actuating part and a lifting magnet which is connected to the lightning contact of the camera and controls the opening time of the central lock.

In a further development of the device according to the invention, the central lock is a mechanical lamella lock and, as an elevator device, has a gearwheel driven by a stepper motor, which meshes with a rack connected to the central lock.

The stepper motor ensures that the central locking mechanism is tensioned very quickly, so that work can be carried out very quickly.

This rapid recording sequence is further supported in the device according to the invention if the elevator device of the central lock has a spring arrangement which supports the movement of the rack controlled by the stepping motor into its starting position. It is particularly advantageous if, in the device according to the invention, the rack is guided with a guide slot and has a pin which cooperates with two end positioners to control the rack movement.

This can be achieved in an advantageous manner that a predetermined sequence of movements is maintained, so that a complete tensioning of the central lock is ensured and no premature opening of the central lock and actuation of the flash unit is possible.

In a development of the device according to the invention, the end position transmitters are designed as fork light barriers along the circumference of the central lock. In this way, it is advantageously achieved that the toothed rod movement during tensioning of the central lock is independent of contacts that are to be closed mechanically.

It is particularly advantageous if, in the device according to the invention, the toothed rack is a circular ring segment arranged parallel to the circumference of the central lock. In this case, an essentially uniform movement of the toothed rack and of the elevator lever connected to it for the central locking takes place without the need for translation arrangements.

In another embodiment of the device according to the invention, the central lock has an electro-optical ceramic component connected to a voltage supply, to which an electrical field is applied after triggering the camera for the desired time interval, in which the ceramic component Serves maximum transparency.

In such an embodiment, use is advantageously made of the fact that electro-optical ceramic components have a simple structure and can be operated in the microsecond range with low energy requirements and low switching times, in order to be switched back and forth between the state of maximum and minimum optical transmission.

The invention is explained below with reference to the description of exemplary embodiments and with reference to the accompanying drawings. The drawing shows in

Figure 1 is a schematic representation of an embodiment of the device according to the invention.

2 shows a plan view, partly with cut-outs, of the central lock of the device according to the invention;

3 shows a side view of the central lock according to FIG. 2; and in

Fig. 4 is a schematic representation of an electro-optical ceramic component for use in the device according to the invention.

The general structure of the device according to the invention is shown in FIG. 1; one recognizes a camera 62 which can be triggered manually or via a connecting cable 65. The camera 62 can be of any commercial type, for example an SLR camera, and has a slot closure (not shown) in the camera housing immediately before the film. In the schematic representation according to FIG. 1, the camera lens 63 is in front of the camera 62 a flash-synchronized camera shutter 64 is set, which has a central shutter 25 as an essential component. However, the camera shutter 64 does not necessarily have to sit in front of the camera lens 63, but can also be built into the camera lens 63 at a suitable point in the lens barrel. With such an arrangement, an object 61 is photographed through the central shutter and the slit shutter, at the same time triggering the electronic flash device 60, which is connected to the camera shutter 64 via the connecting cable 66.

FIG. 2 shows a top view of the outer or flash-synchronized camera shutter 64, which is built into the lens barrel of the camera 62.

The camera shutter 64 is arranged on a carrier plate 10 which is mounted on the camera housing with fastenings passing through bores 11. In the lower area of FIG. 2, a lifting magnet 12 can be seen, which is connected to the trigger 14 of the central lock 25 via an actuating part 13. The actuation of the lifting magnet to trigger the central lock 25 takes place with the control described in more detail below, after the central lock 25 has been tensioned and its elevator device 30 has returned to its starting position.

In order to be able to check the adjustment of the entire arrangement without triggering the camera 62, an actuator 17 connected to an actuating part 18 is provided on the central lock 25 and is articulated on a pin 16 on the side opposite the actuating part 18. The opening or closing of the central lock 25 by means of the actuator 17 via a control 19, which is only indicated schematically in FIG. 3. Here, for. B. a wire release can be used to open the central shutter for the desired time for the viewfinder.

In the upper area of FIG. 2, the elevator device 30 for the central lock 25 can be seen. The elevator device 30 is actuated by means of a stepping motor 31 which is attached to the carrier plate 10 with an adjustable socket 34, a fixing screw 35 for its fastening and adjustment serves. At the front, the stepper motor 31 is held in a bearing plate 32, with spacers 36 with fastenings 33 ensuring the correct arrangement of the bearing plate 32 and the stepper motor 31.

In addition to the central lock 25, a reciprocating rack 50 is provided, which has a guide slot 52 in its center, which is in engagement with two fastenings 33 and is guided by these. The ten bar 50 is connected to the elevator lever 41 for the central lock 25 and takes it with it when it moves along the circumference of the central lock 25. On its upper side, the rack 50 is provided with a toothing 51 which is in engagement with a toothed wheel 37 which is fastened on the axis of the stepping motor 31.

Furthermore, a spring arrangement is provided to support the return movement of the rack 50 into its starting position. This spring arrangement has a tension spring 38, which is mounted with a bracket 39 on the carrier plate 10 and with a bracket 40 on the rack 50. A pin 55 on the back of the rack 50 moves with it along an arcuate path and passes through two sensors 53 and 54 for the two end positions of the rack 50, which it assumes in the starting position or in the clamping position of the central lock. These sensors 53 and 54 for the end positions of the rack 50 can consist, for example, of fork light barriers, so that the pin 33 in the corresponding slots 56 allows the light beam to pass through or interrupt it.

The device described above works as follows: If the entire device is ready for operation and the camera 62 is tensioned, it can be triggered manually or via an electrical pulse via the connecting cable 65. At this moment, the slit shutter in the camera 62 opens for a relatively long time interval on the order of 1/15 seconds. The central shutter 25 of the camera shutter 64 is opened with a certain delay via the X contact or lightning contact of the camera 62, and is opened for a substantially shorter time interval, for example for 1/500 seconds. The central shutter 25, in turn, also actuates the electronic flash device 60 with a short time delay via its X contact or flash contact and triggers the flash light with approximately 1/1000 seconds.

In this way it is ensured that the individual time intervals do not overlap, but are nested in one another and thus ensure that the flash light is fully utilized.

The central lock 25 is opened via the trigger 14 and the actuating part 13 is connected to the solenoid 12, the pulse length of which specifies the opening time of the central lock 25.

The entire device is then re-tensioned, the camera shutter 64 being tensioned with the elevator device 30. The pin 55 is in the starting position shown in Fig. 2, i. H. the light barrier of the second transmitter 54 is open and the light barrier of the first transmitter 53 is interrupted.

As soon as the central lock 25 has been triggered, the stepper motor 31 receives a corresponding signal and moves the rack 50 to the left by the engagement of its gear 37 with external teeth 51 in the arrangement according to FIG. 2, until the pin 55 blocks the light beam from the light barrier in the second Encoder 54 interrupts. At this moment the tensioning position of the elevator lever 41 of the central lock 25 is reached, and the stepper motor receives a corresponding signal and stops. Immediately afterwards, the stepper motor 31 is reversed and moves the rack 50 back into the starting position according to FIG. 2, this restoring of the rack 50 being supported by the tension spring 38 of the spring arrangement. As soon as the pin 55 in the light beam of the light barrier

Interrupts encoder 53, the movement of the stepper motor 31 is interrupted; the central lock 25 is now ready for further reception, so that the process can run again.

In the device described above, the rack 50 moves particularly evenly if it is designed in the form of a circular ring segment which is parallel to the circumference of the central lock ses 25 runs. The movement of the rack 50 is supported by the guide slot 52. The use of the stepper motor 31 has the advantage that the rack 50 does not cause any problems when reversing to move the toothed rack back and forth.

Another advantage of the device is that the camera shutter 64 does not require a complete light density, since this is guaranteed by the actual camera shutter, namely the slit shutter in the camera 62.

With the arrangement described above, a recording sequence of 0.3 to 0.4 seconds can be achieved, the time interval for tensioning the central lock 25 itself being approximately 0.25 seconds. The delay from actuating the lightning contact of the camera 62 to opening the central lock 25 is approximately 15 to 20 milliseconds.

The above statements for the central lock 25 apply in principle to all designs of slat locks, regardless of whether the movement of the slats takes place mechanically or magnetically, as well as for rotor, segment or hole closures.

Another embodiment for the central lock is shown in FIG. 4. This is essentially an electro-optical ceramic component 68, which consists of lead zirconate titanate and with

Lanthanum is doped, such electro-optical ceramic components being produced in a sintering process. On the surfaces of the ceramic component 68, electrodes 69 can be recognized, which are transparent and can consist of tin indium oxide. This

Electrodes 69 are connected to a voltage via lines 69a Supply 67 connected to control the light transmission of the electro-optic ceramic component 68. If a suitable voltage of the order of a few hundred volts is applied to the electrodes 69 and an electric field is thus generated in the direction of the double arrow 70, the ceramic component 68 becomes translucent, the direction of transmission of the light being indicated by the double arrow 71.

Such an arrangement serves the same purpose as the central closure described above, since the ceramic component 68 is normally opaque and can be made translucent for a short period of time for a predetermined time, so that the closure function is performed without requiring considerable mechanical effort. It can be used in an advantageous manner that there is no image field limitation and no glare and extremely short exposure times can be achieved.

The two embodiments of the device described above can be used for a wide variety of applications to photograph rapidly moving objects. Such a device can be used, for example, in connection with traffic monitoring devices, for example to deliver images of motor vehicles from the front or rear that disregard red signals at traffic lights or exceed maximum speeds.

If a slat shutter is used as the central shutter in front of the camera lens, this can have a certain aperture effect even with very large apertures in the camera, but this has been the practice showed that a large number of flash shots are taken with an aperture value of 5.6 or 8 anyway. With such aperture values, however, no significant disturbance due to the aperture effect of the central lock can be observed. If camera lenses with larger focal lengths or telephoto lenses are used, it is found that there is no significant aperture effect even at aperture 4 and that the light losses due to the edge shading are negligible at these aperture values. In particular when used with traffic monitoring devices, it has been shown that the device described above is particularly well suited for the production of photographic recordings of moving objects, since the cited values for the aperture and the exposure time of the camera enable very good recordings at the speeds in question.

Claims

1. A process for the production of photographic images of moving objects, in which the object is illuminated with flash light and the illuminated object is photographed with a camera synchronized with the flash light, which has two closures connected in series, characterized in that when the camera is triggered, an in the camera housing built-in slit shutter is opened as the first shutter, that the opening of the second shutter, which is designed as a central shutter, is controlled by the first shutter of the camera via its flash contact and that the triggering of the flash light is in turn controlled by the second shutter via its flash contact, so that total flash interval in the opening interval of the second shutter and this is completely in the opening interval of the first shutter.

2. The method according to claim 1, characterized in that one works with nested time intervals that are of the order of magnitude 1/15 seconds for the first shutter, 1/500 seconds for the second shutter and 1/1000 seconds for the flash light.

3. Device for producing photographic recordings of moving objects, with a camera, with a first shutter built into the camera, with a second shutter connected in front of the camera, which can be opened for camera adjustment independently of the camera release, and with a flash device connected to the camera, the first shutter being opened when the camera is triggered and the second shutter being opened to expose the film during its opening interval, characterized in that the second shutter (64) is designed as a central shutter (25), which is installed in the lens barrel in front of or in the camera lens (63) and connected to the flash contact of the camera (62), so that

Triggering the camera (62) with its considerably shorter shutter speeds than the first shutter is opened by the flash contact, and that the central shutter (25) is in turn connected to the flash contact of the flash unit (60) and the delivery of the flash pulses within the opening intervals of the two locks controls.

4. The device according to claim 3, characterized in that the actuating device of the central lock (25) has a trigger (14), an actuating part (13) and a lifting magnet (12) which is connected to the lightning contact of the camera (62) and controls the opening time of the central lock (25).

5. The device according to claim 3 or 4, characterized in that the central closure (25) is a mechanical lamella closure and as

Elevator device has a toothed wheel (37) driven by a stepper motor (31), which meshes with a toothed rack (41, 50) connected to the central lock (25).

6. Device according to one of claims 3 to 5, characterized in that the winding device direction of the central lock (25) has a spring arrangement (38-40) which supports the movement of the rack (50) controlled by the stepper motor (31) into its starting position .

7. Device according to one of claims 3 to 6, characterized in that the rack (50) is guided with a guide slot (52) and has a pin (55) which cooperates with two end position sensors (53, 54) to control the rack movement .

8. Device according to one of claims 3 to 7, characterized in that the end position encoder are formed as fork light barriers (53, 54) along the circumference of the central lock (25).

9. Device according to one of claims 3 to 8 ,. characterized in that the toothed rack (50) is a circular ring segment arranged parallel to the circumference of the central lock (25).

10. The device according to claim 3, characterized in that the central closure has an electro-optical ceramic component connected to a voltage supply, to which, after triggering the camera (62), an electrical field is applied for the desired time interval, in which the ceramic component has maximum transparency.