DE2916571A1 - CAMERA WITH AUTOMATIC FOCUS - Google Patents

Description

Patent Attorneys Di ρ I.-1 ng. Curt Wallach

9Q1RR71 Dipl.-Ing. Qünther Koch

ZJfIDOM Dipl.-Phys.Dr.Tino Haibach

& Dipl.-Ing. Rainer Feldkamp

D-8000 Munich 2 ■ Kaufingerstraße 8 · Telephone (0 89) 24 02 75 · Telex 5 29 513 wakai d

_Date: April 24, 1979

Our reference: 16 604 - Κ / Αρ

Applicant: Polaroid Corporation

549 Technology Square
Cambridge, Mass. 02139
United States

Designation: camera with automatic

Focus

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The invention relates to an autofocus camera capable of capturing the subject to be displayed sharply when an earner cycle is initiated.

In DE-OS 2 74-4-093 is a camera with automatic Focusing described in which the initiation of a camera cycle causes the lens or a Lens of the lens from a parking position to a focusing position is transferred, which is dependent on the recording distance, which of a distance measuring system is determined. If an exposure cycle in a Such a camera is initiated, the distance measuring system emits a burst of ultrasonic energy after the Subject off. The time interval between broadcasts of the pulse burst and reception of an echo represents a parameter that has a fixed scaling factor is related to the object distance and the relationship between the object distance and the position of the Defined lens in the camera, in which an image of the subject at that subject distance is sharp the image plane of the camera is mapped. The lens / subject function provides that range of shooting distances in which shooting objects are moved by of the lens carrier can be imaged in focus.

After the range parameter is determined, a motor moves the objective or the objective lens in question in the focus position that depends on the object distance

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ORIGINAL INSPECTED

depends. Then the camera shutter is released to one To cause exposure of the film located in the image plane behind the shutter. When the completion of the exposure is detected, the motor is caused to return the lens to its park position.

In the case of a photoelectrically controlled shutter which is arranged in such a camera, a correct Exposure and focus can be maintained at all times when the exposure cycle is initiated. This is however, this is not the case when the subject is in a close range and the subject distance is smaller is as a minimum distance given by the design of the optical system, or if below Flash illumination of the subject is outside a predetermined range of distances, depending from the range of exposure experts of the shutter and the light output of the flash unit. In the case of daylight shots, you get an insufficiently focused image if the object distance is smaller than a minimum shooting distance. With flash lighting you get an overexposed picture if the object distance is smaller than the minimum predetermined subject distance, and an underexposed photograph results when the subject is further away than the maximum predetermined range.

The invention is therefore based on the object of creating a novel and improved camera for the camera operation to control according to the object distance.

Another object of the invention is to provide a camera

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2316571

to create that is able to limit the camera as far as the shooting distance is concerned, and both in daylight shots and in flash shots.

According to the invention is a display device, the camera with automatic focusing and this responds to a display when the camera cycle is initiated to deliver and / or to block the further camera sequence, when the subject is too close to the camera to focus, or when it is too close to the camera for proper flash exposure. Under Under these aforementioned conditions, a signal is generated which ends the camera cycle without closing the shutter actuate. When the camera operates in the flash mode and the subject is outside of a predetermined range in which the "shutter is able to produce a properly exposed photograph provides the Display device information according to which the subject is either too close to the camera or too far away for proper flash exposure. In In this case, a locking signal is also generated, which terminates the camera sequence without triggering the shutter.

According to one embodiment of the invention, display and / or blocking signals are generated in accordance with the movement of the lens wearer generated when the range parameter provided by the range finder hits the lens below the cannot focus on the given conditions. then

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causes the lock signal that the objective or the objective lens is returned to the starting position without operating the shutter.

According to a further exemplary embodiment of the invention, a digital or analog logic circuit is connected used with the generation of the range parameter to generate the display and .lock signals. This arrangement creates the possibility of ending the camera cycle without the objective lens or objective lens being in its parking position to drive out.

Exemplary embodiments of the invention are described below with reference to the drawing. In the drawing show:

Fig. Ί a schematic block diagram of a self-focusing Camera of the type described, with the various positions of the lens barrel in relation to objects that are too closely adjacent or too far away are,

Fig. 2 is a block diagram of the camera of Fig. 1 showing the distance measuring and focusing arrangement illustrated according to the invention,

FIG. 2A is a time diagram which is assigned to the block diagram of FIG. 2,

3 is a block diagram of a second embodiment of the invention,

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4 shows a schematic representation of the area counter and decoders according to Pig. 3 »

Fig. 5 is a graph showing the relationship zxri -schen the stored count of the area counter and the recording distance can be recognized,

Fig. 6 is a logic circuit diagram of the display and blocking arrangement according to Fig. 3-,

Fig. 7 timing diagrams showing an analog embodiment the display and locking device according to Fig. 3 are assigned,

Fig. 8 is a typical block diagram for generating the Analog voltages according to Fig. 7 »

9 shows a logic circuit diagram for generating displays for the area too close and too far as well as for Generation of the camera blocking signal from the analog system according to FIG. 8.

Reference is first made to FIG. 1 below. The reference numeral 10 applies to an automatically focusing camera, which has a housing 11 with image plane 12 which defines the recording station behind a shutter 13, which can be assigned to a photodetector, not shown, to the entering through the shutter Determine the amount of light when the shutter is open is. An unillustrated sheet of photosensitive material is placed in the image plane to be viewed from the

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photographing scene to be exposed when the shutter mechanism is operated. A lens 14 is of carried an axial end of an adjustable lens holder 15 having a sleeve 16 which is internally threaded is provided which runs on an externally threaded tube 17 of the camera body, so that the lens carrier rotated and thereby the lens 14 can be axially displaced.

The lens 14 has a given lens / subject function, which determines the axial position of the lens at which a subject 18 is focused. the Teeth of a pinion mesh with a ring gear on the circumference of the lens carrier 15 »so that a rotation of the pinion 19 transmits a rotary movement to the lens carrier by a motor 20, so that the lens 14 is axially displaced. Rotation of the pinion in one direction (i.e., clockwise) causes rotation of the lens carrier counterclockwise and moves it to the right as shown in FIG. 1 from the parking position in close proximity to the housing. In the parked position of the lens 14, the end face 21 of the lens carrier 15 lies in that indicated by the line 21A Position. Line 21B shows the location of face 21 when lens 14 is in position that it occupies at the shortest shooting distance, in which an error-free focus setting is possible.

If necessary, the movement of the lens carrier in one direction can be limited after the near position. In such a case, a stop could pass through the closed end (shown in phantom) of a slot

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22 are formed in the inner surface of the sleeve 17, which cooperates with a fixed pin 23 which is fixed to the tube 7 and protrudes into the slot. A twist of the The counter-clockwise pinion causes the lens carrier to move in the opposite direction and leads this back to its parking position, where it strikes the housing 11, whereby the further movement in the opposite Direction is limited.

When the lens wearer is in the sewing position 21B is, then the object 18 is shown in focus when it is in a close range plane 24 at a certain minimum distance whose absolute vert is dependent on the lens / object function and on the mechanics of the lens wearer, which is determined by the camera manufacturer. When the lens wearer is in the "hyperfocal" position 21C is located, the subject 18 is imaged in focus when it lies in the “hyperfocal” plane 25 or even further. Accordingly, an image of a subject that is in a subject removal range lies between the levels 24 and 25 of FIG. 1, in which The camera's image plane can be brought into focus by changing the location of the lens wearer is selected according to the lens recording distance function within the near and far range limits will. An object that is closer to the camera than the minimum distance can no longer be focused because the lens barrel cannot be moved beyond the near position 21D.

The camera 10 also has a range finder 26 with an acoustic measuring member 36 and one through a Release button 28 actuated blocking sensor 27. At the

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By manually depressing the release button, a switch (not shown) is closed and there is a camera cycle initiated, wherein the range finder 26 generates a distance parameter that is directly dependent on the object distance, and it becomes from this parameter determines a number that represents the focus position of the lens wearer according to the lens / object function. This number also represents the subject distance of the subject from the camera.

A drive 20 responds to the number calculated by the range finder and drives the lens carrier 15 from the Park position in the focus position by the pinion 19 is rotated in a suitable manner. Once the Lens wearer is in the position for focusing, a shutter 13 is operated to not to expose the photosensitive sheet shown, which lies in the image plane 12. The shutter 13 then signals the completion of the exposure and the drive responds in such a way that the lens carrier 15 is in the parking position is fed back, whereby the camera cycle is ended.

This above-described mode of operation of the camera 10 enables the recording of an object without knowledge of the Shooting distance, as the focus in the described Way done. Only if the object distance is smaller than the minimum that can be detected by the camera Distance, insufficient focus is obtained.

When the ambient lighting condition is poor so that there is insufficient exposure, if not one

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Time exposure is carried out, then the camera can be switched from daylight mode to flash mode. Such a switchover can be accomplished by attaching a flash unit, for the sake of simplicity However, the description is the camera 10 according to the illustrated embodiment with a fixed flash unit 29 provided to record the subject 18, the illumination by a flash lamp or an electronic flash 30 occurs when the switch 31 of Daylight mode is switched to flash mode. The latter position is indicated by dashed lines 31A indicated. The line 45 that the flash device 29 with the Camera connects, causes the synchronization of the speed camera excitation with regard to the sequence of the shutter 13 in conventional way.

Since camera exposure systems do not provide an unlimited range of exposure values (available combinations of aperture size and exposure times), represent minimum and maximum exposure values that correspond to the shutter, respectively are important aspects of flash photography when the flash energy is fixed Has value. As a result, proper flash exposure can only be achieved within a limited range of shooting distances be performed. If z. B. the minimum exposure value is designed so that a correct Exposure occurs when the subject is in plane 24, then an exposure is made Object that is brought even closer to the camera, d. H. lies in plane 33, overexposed while Objects are underexposed at long distances. Although the focusing distance (level 24), the

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defines the minimal object extension in which one more Focusing may be required, often differentiated from the minimum distance, "at which a flash illumination still leads to a correct exposure, these two distances should be equated here. In addition, level 34 was chosen to be the maximum Specifies the distance below which a subject can still be properly exposed with flash lighting. Accordingly, the distance between planes 24 and 34 represents the flash illumination area in which a subject is to be photographed can still be properly exposed. Therefore, the use of the camera 10 in the flash operation works without prior Knowing the shooting distance leads to a correct exposure only when the subject is between the Levels 24 and 34- is located.

In order to obtain properly focused images in daylight operation, regardless of the distance to the object, and to properly exposed pictures with flash lighting without prior knowledge of the shooting distance To obtain, the invention provides a display device in a camera with automatic focusing and / or a camera lock that takes effect when the subject is properly focused is too close or out of range for proper exposure under flash lighting to do this Alert and warn the user of the existence of these conditions and allow further operation of the camera lock.

In the exemplary embodiment according to FIGS. 1 and 2, the display device 35 operates according to mechanical scanning

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the position of the lens wearer after this through the Rangefinder was set to focus while in the embodiment of FIG. 3, the display device 35A is actuated according to the output of the distance measuring system before any movement of the Lens carrier takes place. In both exemplary embodiments, the display device responds to the initiation of a Camera cycle to provide an indication when the subject is too close to the camera to properly focused or out of range (too close or too far) of the subject in which a correct exposure can take place in flash mode. A locking signal is also generated and the camera cycle ends without the shutter being released.

The camera described here has a single camera cycle with distance measurement, focusing and exposure on. It is clear, however, that it is often useful to provide means that the camera cycle only over the Allow distance measurement and focus to run. Even in the latter case, however, is the novel display device effective in the manner described.

Reference is now made to FIG. 2 of the drawing. Here is a block diagram showing how it works in the following in connection with two recording situations is described:

(1) Daylight exposure with a subject having a subject distance that is greater than the cock setting, or a flash

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lighting shot, with the subject within of a predetermined distance range within which a correct exposure under flash lighting he follows;

(2) a daylight recording in which the subject has an object distance that is smaller than the close-up focusing distance or a flash light exposure, wherein the subject is outside of the predetermined range, which is a correct one Exposure allows.

The former situation represents normal operation as described below.

A camera cycle is started by depressing the camera release button 28 (Fig. 2) initiated. This connects the camera to a battery 44 and becomes the range finder 26 actuated by setting up a step function whose leading edge is established at 47 and is used to switch an acoustic distance measuring device 36, at the same time a timer 58 is started will. The distance measuring device 36 radiates ultrasonic energy 60 which is directed at the subject 18 is directed. The one reflected from the subject Energy is received by the acoustic range finder 36 and causes the latter to be a receiving or To deliver range pulse 48 at time τ after transmission (Fig. 2A). During this interval the Timer 58 a periodic pulse train, whereby a Counter 60 is filled, while a decoder 62 is used to decode the content of the counter 60 and the

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Breakthrough points of an approximation of the lens / object function to create. A programmed divider 63, responsive to the output of decoder 62, operates as a scaled timer whose pulse repetition frequency changes according to the approximation of the lens / object function changes, which in turn is parametrically related to time, according to the relationship between the interval τ and the object distance. The output of the divider 63 is the distance counter via an AND gate 40 and an OR gate 42 41 supplied.

A latch circuit 64 initially activated by the Transmission signal is set, it is reset when the pulse is received. Accordingly, the output of latch 64 is a pulse of duration T and accordingly becomes Gate 40 dui> ch the locking member 64 only during that Time interval between the start of the transmission of the acoustic rangefinder 36 and the reception of the Echoes released by this range finder.

At the moment when an ultrasonic pulse is emitted, the scaled clock is based on a distance counter 41 unlocked. In the time interval between the start of the broadcast and the earliest point in time at which the recipient was received is able to detect an echo (here is the sending time of the echo and the blanking time of the receiver which are required to prepare it for an echo), the scaled clock has p ^. Pulses generated, where p ^, is a number that represents both the The close-up setting of the lens carrier as well as the minimum shooting distance of the camera represents (Fig. 1). The scaled clock continues to generate pulses with a

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Rate which is determined by the program of the divider 63, so that when an echo pulse 48 occurs and the gate 40 closes, the content of the counter 41 becomes ρ, where ρ is a number which represents both the focussing position of the lens wearer and the object distance. As explained below, the maximum number of pulses that can be input to the counter 41 by the clock is equal to p ~, where p _o = »p =» p ^ ,, and Pp is a number that corresponds to the hyperfocal position of the lens wearer.

Initially, the lens wearer is in its parking position, which is assigned the number p, where p ^ == - Pp is. In order to achieve this focus position, which is represented by the number ρ (stored in the distance counter 41) the lens must be displaced a distance proportional to Pv - ρ. This result will is achieved by a decoder 43 which generates a focus control signal when the content of the counter 41 reaches the Number p, reached. The distance counter is based on the value ρ is increasingly filled in a manner to be described by the displacement of the lens carrier.

In addition to the closing of the gate 40 and the termination of the counter filling by the scaled clock, the Echo pulse 48 also includes a trailing edge lock circuit 65 which includes AND gate 68 and AND gate 66 unlocks. The activation of the gate 66. causes the motor 32 of the drive 20 via the forward motor control 67 is fed, while the gate 68 allows the lens setting pulses to reach the gate 42 and the distance counter 41. This is how the electricity comes from the battery

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44 is fed to the forward motor control 67, which excites the motor 32 which is coupled to the lens carrier 15 via the pinion 19. The motor 32 moves the lens carrier and thereby actuates the auxiliary pulse generator 37.This auxiliary pulse generator 37 accordingly only generates pulses when the motor 32 moves the lens carrier, the speed at which the pulses are generated being dependent on the speed at which the Motor moves the lens carrier. The total number of pulses this produces is proportional to the distance the lens wearer has moved. These pulses are fed to the counter 41 via the gate 68 (this is enabled by setting the locking circuit 65 after receipt of the echo pulse 48) and to the OR gate 42.

Accordingly, the content of the counter 41 increases from ρ (a number representing the focus of the lens wearer represented) after the filling position, d. H. after the number p-z. When the content of the counter 41 reaches p, then generated the decoder 43 a focus control signal which resets the latch circuit 65 and thereby the gate 66 opens, so that the forward motor control 67 is blocked and accordingly the motor 32 and the lens carrier be shut down. In addition, the focus control signal is which is generated by the decoder 43, via a delay stage 38 and a normally open Gate 39 fed to the shutter drive 69, which lets the shutter 13 run down, whereby the in the image plane 12 Ulm lying on the camera is exposed. A blocking sensor 27, which has a clock 80, a blocking counter 74 and a decoder 82, causes the Distance counter 41 and generates a accordingly

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Focus control signal when a mechanical blockage or jamming occurs.

When the camera is used in daylight operation, the switch 31 has the fully extended position in FIG and the flash unit 29 is switched off. If the camera is operated with flash lighting, then it is located the switch 31 is in position 31A, whereby the Triggering of the flash 30 is synchronized with the shutter in a conventional manner. In any case it will the exposure controlled by a photocell, not shown, which integrates the light in a conventional manner, that falls on the film as a result of the actuation of the shutter, xirobhen the exposure is terminated, when a predetermined amount of light has struck the film.

Completion of the exposure is detected at 49, triggering a monostable multivibrator 70, which generates a voltage for a predetermined period of time, during which period the gate 71 is enabled so that current from the battery 44 can flow to the reverse motor control 72, which is effective is opposite to the drive motor 32 in one direction to drive the direction in which the controller 67 was driving the motor. In this way, the engine performs the Lens carrier 15 from the focusing position into the Park position back. A coupling, not shown, prevents the motor from burning out when the lens is the Has reached the parking position and before the period of time set by the multivibrator 70 has expired. Instead, a lens switch (not shown) can be used to switch off the voltage when the

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Lens reaches this parking position.

In this way the camera cycle has ended and this cycle begins with the manual actuation of the camera trigger, when the lens wearer is in its parked position. The cycle includes the movement of the lens carrier after the focus position, the completion of the exposure and the movement of the lens wearer back in the parking position.

When the camera is used in daylight and the subject is at a distance to be photographed that is greater than the hyperfocal distance, then the scaled clock reaches the number p ~, and this corresponds to the hyperfocal distance, which is about 7 πι, before a range pulse 48 appears and before the latch 64 can be reset. Consequently the divider generates a signal on line 63A which is fed to latch circuit 64 and this resets when the count of the divider 63 is the hyperfocal distance reached before pulse 48 occurs. In this case, the area counter 41 contains the numbers pp and this corresponds to the hyperfocal position of the lens wearer. The setting of the latch circuit 65 causes a release of the motor 32, which transfers the lens wearer from the parking position to the hyperfocal position. It is hence it is clear that a subject is in focus at a distance greater than the hyperfocal distance is because the lens wearer is moving to its hyperfocal position.

The display device 35 becomes effective when the above

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• 26 ·

specified second situation occurs, namely when the camera is set to daylight operation and the The subject is at a distance that is shorter than the closest focusing distance, or when the camera is switched to flash mode and the subject is outside the usable area for flash mode is located. Let us first assume that an Earnera cycle is initiated when the camera is switched to daylight mode and the subject is in a Level 33 is located, i.e. H. too close to the camera to allow focus. In this case it causes the motor 32, that the lens carrier 15 from its color graduation is transferred to the position 21D in Fig. 1, in which the lens carrier closes the break contact 50 which is present in the recess in which the lens carrier is slidable is. This switch is closed as soon as the lens wearer passes through position 21B and in any case before the focus control signal is fed to the shutter drive 69, and this is ensured by the delay stage 38.

Closing the switch 50 applies the indicator light 84- Voltage and supplies the UliD gate via the ODJSR gate 85 86 a signal. At the same time, the focus control signal is applied to the other input of AND gate 86, which causes the MD gate to provide an output signal that blocks the gate 39 and the monostable Multivibrator 70 triggers. The blocking of gate 39 prevents the focus control signal, after being delayed at 38, from the shutter operator 69 fed x ^ rird. In this way it results that a movement of the lens carrier over the position 2MB

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(Pig. 1) also locks the shutter according to the operation of the range finder 26 and at the same time the multivibrator 70 releases the lens wearer in the parking position returns to complete the exposure cycle. In addition, the user is drawn to the impermissibly short shooting distance pointed out, since the indicator lamp 84 lights up, which can be designed as a light-emitting diode 84 and lies in the viewfinder 87 of the camera, as shown in FIG. Accordingly, if an attempt is made take a picture of a subject in daylight, and the subject closer to the camera is the minimum distance for which the optical system is designed, then the display device delivers 35 a signal for the display and a lock signal, which ended the exposure cycle without having released the shutter. In addition, the locking signal causes the Lens carrier is returned to its parking position.

When the camera works in flash mode and the switch 31 is in position 3 ^ A and when the subject z. B. lies in plane 33, i. H. too close to the camera for proper exposure taking To be able to perform flash lighting, the display device 35 also becomes effective and prevents exposure. As described above, initiation of the camera cycle causes motor 32 to disengage the lens carrier Park position moved to position 21D (Fig. 1), which in turn the switch 50 is closed. The display device 35 reacts in the same way as described above and blocks the exposure and ends the exposure cycle.

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When the camera operates in the flash mode and the subject is behind level 34, d. H. if it is too far away to be properly flashed Carrying out exposure, the initiation of the exposure cycle causes the motor 32 to fully extend the lens carrier from the parking pitch to that shown in FIG position shown transferred. In this position, the lens wearer comes free from the normally closed contact 5I, which is in the Housing 11 is arranged and is only actuated by the lens carrier when the latter is in one position that applies to object distances that are smaller than the maximum distance for flash lighting that is defined by plane 34. Therefore, the lens wearer gives the switch for objects behind level 34 51 free and this is closed when the lens wearer is moved to a position that corresponds to a too far shooting distance.

From Fig. 2 it can be seen that when the focus control signal occurs all inputs of AND gate 87 occur simultaneously, and this gate then has an output generated by decoder 43. The output of the AND gate 87 causes the lamp 88 to light up, which is also arranged in the viewfinder 87 and indicates that the subject is beyond the maximum Distance at which a flash exposure can still be taken. In addition, the output of the AND gate runs 87 through the OR gate 85 and is fed to the AND gate 86 which generates a lock signal which the Gate 39 blocks and prevents the delayed focus control signal from actuating drive 69. aside from that the locking signal is fed to the multivibrator 70 so that

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the motor 32 returns the lens carrier to the park position, thereby terminating the exposure cycle without that the shutter can be operated.

In this way, the display device 35 according to FIG. 1 is only effective after the lens wearer has moved out of the parking position moved to the focus position. The decision to terminate the exposure cycle without actuation the shutter is effected on the basis of the focus position of the lens wearer. It can too other switching arrangements apply to the focus position of the lens wearer and to provide indications and locking signals, as mentioned above became. Regardless of the circuit arrangement used, however, the display device 35 always effects a display when the subject is at a shorter distance than it corresponds to the false setting which the optical system of the camera is designed, and also whenever the subject is out of range in which proper flash lighting can be performed when the camera is on flash mode is switched. Whenever an indication is provided, a locking signal is also generated indicating a shutter actuation prevented and ends the camera cycle.

Fig. 3 describes a further embodiment at xtfelchem that actuated through the lens of the objective Too near / too far system replaced by a 35-A display whose mode of operation depends on the content of the distance counter 4-1 and not on the physical one Movement of the lens carrier. The camera according to FIG. 3 corresponds to that according to FIG. 2 with the exception of the modifications,

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required to customize the display device 35A. Since a lens movement is not required in the third and fourth exemplary embodiment in order to adjust the object distance display and / or block the exposure, these exemplary embodiments are in contrast to the exemplary embodiment according to Fig.?. Also suitable for use in connection with flash object distances with fixed focus cameras. The counter 4-1 is a typical binary counter and, for purposes of discussion, the counter in FIG a 4-bit binary counter is shown. With a working More camera bits are required to increase the number of divisions into which the range of shooting distances can be divided. However, the principle of operation is the same.

The counter 4-1 is filled by the output of the scaled clock 63 in the manner described above. The counting state of the counter 4-1 is a function of time and the output of the scaled clock generator according to FIG. 5. Each state is assigned both a position of the lens carrier, as described above, and the distance of the object. That is, if the counter 4-1 has the status 0011 when the reception pulse 4-8 occurs, then the distance of the object generating this pulse may be 90 cm, if the table according to FIG. 5 is used as an aid. Assuming the minimum distance that the camera's optical system can be adjusted to be 120 cm, then the minimum distance from the camera can be any of the four conditions that are within the range "too close for flash or focus.""are included. These states can be expressed by the logical variable 03'Q ² F. this is the

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logical operation performed by AND gate 90 (Fig. 6). This gate has an output xr while the first three counts of counter 4-1. When a receive pulse 4-8 occurs during this time, then it can be concluded that the subject is closer to of the camera is greater than the minimum distance defined by plane 24 (Fig. 1).

As shown in Fig. 6, under these conditions, a latch circuit 91 is set, causing the lamp 84A is energized, indicating that the subject is too close to focus in daylight, or too close to get a proper exposure under flash lighting. The output of the latch circuit 91 passes through an OR gate 92 to generate a camera lock signal which gate 93 Disables and prevents the delayed output of the latch circuit 65 from enabling the gate 66 and the lens carrier motor 32 starts up. That is, the lock signal appears in time before the time-delayed output of the latch circuit 65 is present, which prevents is that the motor 32 is applied to voltage. Consequently the lens wearer remains in its parking position. In addition, the blocking signal generated by the OR gate 92 blocks the gate 39 i ^ nd prevents the shutter drive 69 a signal is provided and the multivibrator 70 is also operated to end the camera cycle. It follows from the above considerations that the camera cycle can be terminated without the lens wearer moves and without "the closure" expires.

When the camera is set to flash mode and the

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Object is at a distance which is greater than the maximum distance which is given by the plane 34- (Fig. 1), then an initiation of the camera cycle causes the distance counter 4-1 to assume one of the five states in the Area ^I: to xireit for lightning "according to FIG. 5 are included. These states can be defined by the logical quantity Q4 - (qi << Q2 + Q3). This logic is carried out by the display device 35A according to FIG the output of the AND gate

95 decisive for an object that is behind level 34-. When AND gate 95 provides an output, when a receive pulse occurs and when the camera is switched to flash mode, then the gate would

96 provide an output representing the latch circuit

97 sets and lights up lamp 88A. This lamp indicates that the subject is too far away to get proper exposure with flash lighting. The latch circuit 97 provides also a camera blocking signal as a result of the OR gate 92, and this is used to enable the gates 66 and 39 and end the camera cycle in the manner described above.

The distribution of the output into those shown in FIG Levels is completely arbitrary. For example, the "usable area for daylight photos" could be larger or smaller than shown, and this depends on the camera design. The size of the area "too close for." Flash "might be different from the" too close to focus "area, and this again depends on the camera design, and the logic required for such other areas depends directly on the

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areas actually used.

Instead of the display device 35-Ä-, which shows the output of the distance counter ^! V \ actuated, a display device according to the invention could also take the form of device 35B in FIG. In this embodiment, the operation of the display device is based on the knowledge that the time required for the output of the scaled clock to reach a number which corresponds to the recording distance depends on the scaling factor of the scaling clock. Accordingly, timing independent of the scaled clock could be used if the timing is synchronized with the scaled clock. A stable relationship to the operation of the scaled clock is a suitable starting point for such timing. Such a stable dependency could be brought about by depressing the shutter release button 28, which starts at "start" according to the timing diagram of FIG. In this case, the circuit 100 according to FIG. 8 supplies the necessary logic inputs to the display device 35B according to FIG.

The circuit 100 comprises an integration stage 101 with a time constant R, C1 and an integration stage 102 with a time constant R, C2 which is greater than the time constant of the stage 101. The time rate of change in the output of these two integrators is shown in FIG. Upon depressing the shutter release button 28, thereby closing the start switch 103, the output of the integrator 101 (shown at TC # 1) reaches a trigger level at time t ^ and this is prior to time t- at which the output of the integrator 102

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BATH ORIGINAL

SI.

(shown at TC Er. 2) reaches the trigger level. Each of the integrator circuits 101 and 102 has inverters, the circuit 101 having a single inverter 104- the output of which changes from N to II at the end of the interval between the closing of the start switch 103 and t ^ changes while the circuit 102 has two inverters 104 and 105, and the output of the latter changes from F to F at the end of the interval between closing the switch and t ™.

By suitable choice of the time constants for the integration elements 101 and 102, the time t _A j corresponds to the time that is required for the distance counter 41 to receive the pulses of the scaled clock which, according to their number, correspond to a subject that is at the minimum distance from the camera is located. Correspondingly, the time t ™ represents the time which is required so that the distance counter 41 can receive the pulses of the scaled clock which, according to their number, correspond to a subject which is located at the maximum distance from the camera.

The display device 35B of FIG. 9 uses the logic signals which are developed by the circuit of FIG. 8, and also the logic signals associated with the receive pulse 48 and the position of the flash switch 31 correspond. If the receive pulse occurs before t- ^ (this corresponds to a position "too close"), then the AND gate 107 is enabled by the received signal and so is the N output of inverter 104. Under these conditions, gate 107 accordingly has an output which is a latch circuit 108 sets by which an indicator lamp 84B

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is made to light up, thereby providing an indication becomes that the subject is too close to the camera in order to be able to focus or properly expose with flash operation. In the same way, in flash mode, indicated by switch 31, an OTO gate 109 is activated by the SFICHT received signal, the strobe operating signal and the F output of the inverter 106 enabled when the receive pulse 48 has not occurred (EEC-) before t ™ occurs (this corresponds to too distant position). Accordingly, among these has The gate 109 conditions an output which sets the latch 110 and thereby the lamp 88B lights up, thus providing an indication that the subject is "beyond the maximum distance for proper exposure is available during flash operation.

As in the case of the display device 35-A-, the display device 35B generates a locking signal via the OR gate 111 whenever either the locking circuit 108 or 110 is set. Such a locking signal is used to set the gates 93 and 39 (.I ¹ Xg. 5) and operate the multivibrator 70.

Accordingly, if the latch circuit 108 is set, a display and disable condition is provided if the receive signal 48 occurs before the N output of the inverter 104 appears (before time t ™ ·), while the latch circuit 107 is set if that Received signal, did not occur before the output of the inverter has changed to 'S (after the time t- ™).

909884 / 0B73

2jUs amm

The invention "relates to a camera with automatic Focusing and a display device that has a Indicates when the subject is too close the camera to focus. In addition, a locking signal is generated when this Recording situation exists, whereby the expiry of the exposure cycle is prevented. If the camera is operating in the flash mode, then the display device provides one Display when the subject is outside of a predetermined range The range in which the shutter mechanism is able to produce a properly exposed photographic image under flash lighting, and there is also a blocking signal under this recording situation supplied, whereby the expiry of the exposure cycle, d. H. the shutter release is prevented.

909884/0573

Claims (20)

1.; Camera for recording an image of a subject, which is within a predetermined range of "object distances" with a range finder that determines the object distance in accordance with a camera operation, and with a A shutter for exposing an image of the subject on a recording material, the Rangefinder generates a pulse train and the total number of generated pulses within the pulse train represents a measure of the distance to an object, characterized in that the range finder a pulse train is generated in such a way that a pulse number range is representative of the object widths within said range and at least one further pulse number range is representative is for object distances outside of this range and that means are additionally provided for providing an indication when the total number of pulses lies within the further pulse number range, thereby indicating that the subject is outside of said range. 2. Camera according to claim 1, characterized in that additional means are provided which the closure block if the total number of pulses is within the wider pulse number range. §09834 / 0573 -? - 3. Camera according to claim 1, characterized in that the display means also provide an indication when the total number of pulses is within a first pulse number range which is representative of an object distance which is less than the lower limit of said range of shooting distances, and Dess the total number of pulses within a second Impulsζahlbereichs greater is representative of a subject distance, than the upper Grenzv / ert said range. 4. Camera according to claim 1, characterized in that the display means provide an indication when the total number of pulses is less than a predetermined one minimum number. 5. Camera according to claim 4, characterized in that the given minimum number is representative of a subject that is in the near limit area is located. 6. Camera according to claim 1, characterized in that the indicating means provide an indication when the total number of pulses is greater than a given maximum Number. 7 · Camera according to claim 5, characterized in that the given maximum number is representative of an object that is in a flash illumination maximum distance. 8. Camera for recording an image of a recording 909884/0573 object, which is in a given range of object distances, with a range finder, which determines the object distance when the camera is released, "and with a shutter to expose a Image of the recording object on a recording material, the range finder being a pulse train generated, the total number of which is representative of the object distance, characterized in that the range finder a pulse train generated such that a pulse number range is representative of the object distance within of said range and at least one further pulse number range is representative of object widths outside this range, and that means are provided to lock the shutter when the total of pulses lies within the wider pulse number range in order to prevent exposure, when the subject is outside said range. 9. Camera according to claim 8, characterized in that the shutter is blocked when the total number of pulses is within a first pulse number range is representative of an object width that is smaller than a lower limit of said Object width range, and that the pulses of the pulse train of a second pulse number range are representative are for object widths that are greater than an upper limit of the said range. 10. Camera according to claim 8, characterized in that the shutter is locked when the total number of Θ09 8.84 / 0Β73 _ Room _ Pulses is less than a given minimum number of pulses. 11. Camera according to claim 10, characterized in that the given minimum number of pulses is representative of a subject that is in the near-range limit position is located. 12. Camera according to claim 8, characterized in that the shutter is locked when the total number of Pulses is greater than a given maximum number. 13 · Camera according to claim 12, characterized in that the given maximum number of pulses is representative of a subject that is in the maximum still usable distance for flash exposure. 14. Camera for recording an image of a subject, that is within a given range of object distances with a range finder, which determines the object distance when the camera is triggered, and with a shutter to expose one Image of the subject on a recording material, characterized in that that the range finder generates a range time interval, the length of which corresponds to the distance of the object, such that a range time interval within a time period of given minimum and maximum limits is representative of an object width within the given range and a range 809884/0673 time interval outside the given time period is representative of an object range outside of said area, and that means are provided which provide an indication when the area time interval, generated by the range finder outside of the mentioned given time period to thereby provide an indication when the subject is outside the mentioned distance range lies. 15 · Camera according to claim 14, characterized in that also means are provided to lock the shutter when the generated range time interval is outside the given time period. 16. A camera according to claim 14, characterized in that an indication is provided when the duration of the generated Area time interval is smaller than the mentioned minimum first time period limit and thereby is representative of an object distance that is smaller than a lower limit value of the distance range or greater than the maximum time period limit and is therefore representative of a recording distance, which is greater than an upper limit value of the specified distance range. 17 · Camera according to claim 14, characterized in that first display means define a first time period which is essentially equal to a range time interval, representative of an object distance at a lower limit of the range, and a second Time period greater than the first and im 90988W0573 substantially equal to an area time interval representative of a subject at which the upper limit of the range mentioned "is located, and that further display means are provided which provide an indication when the generated range time interval is within the first or second time period lies. 18. A camera according to claim 14, characterized in that the rangefinder energy according to the subject emits and receives a reflected signal from it and that the time between emission and Reception forms the area time interval. 19. A camera according to claim 18, characterized in that the range finder is a sound range finder is. 20. Camera for recording an image of a subject within a given range of object distances with a range finder according to the camera release determines the distance to the subject, and with a shutter for exposure an image of the subject on a recording medium, characterized in that the range finder has a range time interval generated, the length of which corresponds to the object distance, such that a range time interval is representative of a given minimum and maximum limits within a time period Object distance within the specified range of object distances and a range time interval 90988A / 0573 - / - outside the given time period is representative of an object range outside the stated range, and that means are also provided which block the closure when the range time interval generated by the rangefinder is outside the given time period, causing an exposure is prevented when the subject is outside the specified distance range. 909884/0573