Agfa-gevaert Ag

Istvan Cocron

Peter Lermann

Kurt Borowski

Otto Stemme

Theodor Huber

Eduard Wagensonner

Gunter Fauth

August Hell

Dieter Engelsmann

Karl Wagner

Wolfgang Ruf

Richard Wick

Reinhard Nicko

When a trigger lever is depressed, both a focus adjuster ring and a control disk commence to rotate in unison, driven by a spring mechanism. Position-sensing switches receive signals indicating which subject-distance setting the focus adjuster ring should be arrested at, and furthermore are opened and closed by the control disk during movement of the latter. When the focus adjuster ring reaches the required subject distance setting, it is arrested and kept arrested, thereby completing an automatic focussing operation, but the control disk continues to turn on to its end position, at which it causes the shutter mechanism of the camera to open and furthermore the exposure-timing circuit of the camera to initiation a scene-light-dependent exposure-timing operation.

Automatic exposure control for automatic-focus cameras

A digital circuit is described for controlling functions of a camera wherein the circuit is powered by a potential source which is connected to the circuit through a relay actuated switch. The circuit employs a plurality of D-flip flops to regulate functions such as film transport and opening and closing of the camera shutter as a function of the light intensity of the scene being photographed. A reset signal generator is used to provide stable and reliable control over the starting condition of the flip flops and render the circuit insensitive to voltage transients as may occur from contact bounce effects at the relay actuated switch. The reset signal generator employs an inverter delay chain to provide like reset pulses when such contact bounce occurs. Various control features are described.

Switching circuit for regulation of camera functions

A distance measuring system generates an in-range signal when an object is located within a range of focus or a zone of protection, as the case may be. The system utilizes a single infrared transmitter and two receivers in order to determine the position of the object by triangulation.

Distance-measuring system with in-range signalling for use with cameras,

A photographic still or motion-picture camera has a viewfinder and a manually moved focus adjuster, such as a focussing ring. When the user peers into the viewfinder, there is a visible indication of the direction in which the focus adjuster should be manually moved to reduce the state-of-focus error, for example two curved illuminated errors, one pointing clockwise and the other counterclockwise, only one of which lights up to indicate the direction in which the focussing ring should be manually turned. When the state-of-focus error has been reduced to zero or a minimum, this is likewise indicated, for example because neither curved arrow is illuminated. To control the activation of the indicating elements, use can be made of components of a conventional completely automatic focussing system, but minus the adjusting motor of such system and minus superfluous motor-energization control circuitry. In this way, the user is provided a simple and unequivocal guide when manually focussing, without the cost, complexity, bulkiness and power consumption of a complete automatic focussing system including an adjusting motor and motor-energization control circuitry.

Photographic camera with state-of-focus indication

A digital control circuit for use in automatic-focus cameras is disclosed, which is suitable for use in self-focusing systems which determine focus by means of triangulation. The system corrects for motor oscillation about a state of proper focus, defocusing caused by inertia, and for an inability to evaluate proper state of focus caused by large distances between the camera and a subject.

Digital control system for automatic-focus cameras

Photographic camera

A focussing system of the type which emits radiation from the camera towards the subject, with the radiation reflected from the subject being incident upon a receiving transducer generating an electrical signal from which focus-control information is derived. The emitted radiant-power level is automatically controlled in dependence upon camera-to-subject distance, preferably in dependence upon the power level of the reflected-back radiation incident upon the receiving transducer, even when the focus-control information required for primary system operation is independent of such power level. This makes possible various important improvements, including: automatic lowering of the emitted-power level in close-up contexts, especially where a danger of eye damage might exist; more generally, automatic matching of emitted-power level to the needs of the signal-processing circuitry, permitting signal-processing stages of narrower operative range to be employed on account of the narrower variations in power level of the signal produced by the receiving transducer; and lowered power consumption. Preferably, when a focussing operation is initiated, the emitted power level is initially low or zero and is progressively increased to an automatically selected value without overshoot.

Focussing system with automatic control of emitted radiant power

At the start of each focussing operation, the camera objective is at a first extreme subject-distance setting and is moved in a first direction therefrom towards the second extreme subject-distance setting. A focus-evaluating circuit comprises first and second photodetectors located to receive light from the subject and a comparing circuit which compares the light incident on the photodetectors and in dependence upon the present subject-distance setting generates first and second signals respectively indicating that the subject-distance setting should be changed in the first direction or in the opposite second direction, such circuit having bidirectional character and furthermore establishing a tolerance range of acceptable distance-setting error within which both the first and second signals are generated. During the unidirectional change of subject-distance setting, the appearance of the first signal leads to generation of a stop signal commanding that the progressive change of distance setting be stopped. Accordingly, the unidirectional change of setting is commanded to stop at the point where the changing distance setting just enters into the tolerance range of the bidirectional evaluating circuitry.

Unidirectional focussing system

A first pulse train whose pulse repetition frequency varies in dependence upon scene light, and a second pulse train whose pulse repetition frequency does not vary in dependence upon scene light, are counted by digital counting circuitry, and a terminate-exposure signal is produced when the digital counting circuitry reaches a predetermined count. The second pulse train serves to establish an upper permissible limit for the duration of the exposure to be performed.

Digital exposure-duration control circuit with upper limit on exposure

Pulses of radiation are emitted from the camera to the subject, reflected back to the camera, and incident upon two detectors. The successive pulses produced by the two detectors are applied to respective integrators which trip respective threshold circuits when and if their integral signals reach the threshold value. This inherently reduces detector and other noise present in the processing circuitry. A tolerance-range counter ascertains whether or not, after one threshold circuit is tripped, the other becomes tripped within a predetermined time interval.

Radiation-emissive focussing system with integration of the signals

First and second photodetector signals, whose relative amplitudes depend upon focus error, are integrated to form respective first and second integral signals whose relative rates of change are dependent upon focus error. Each integral signal is applied to two comparators, one whose threshold level is reached first and the other having a threshold level which would be reached second. When one or the other of the two integral signals reaches its first-reached threshold level, this applies a corresponding signal to the data input of a respective flip-flop, and when this faster-changing integral signal then reaches its second-reached threshold level this clocks both such flip-flops. The time elapsing between the faster-changing integral signal reaching its first-reached and then its second-reached threshold level constitutes a tolerance interval, during which the slower-changing integral signal is given an opportunity to try to reach its respective first-reached threshold level. If the slower-changing integral signal reaches its first-reached threshold level within the tolerance interval, then a corresponding signal is applied to the data input of its associated flip-flop as well before the two flip-flops are clocked, with the result that the states of the two flip-flops are the same as if both integral signals had indentical rates of change of value.

Focussing system for cameras

A camera includes a viewfinder, an objective and a manually operated focus adjuster. An optical system located in the path of incoming image light splits the incoming image light beam into two component beams projected into respective first and second focal planes. First and second planar arrays of photosensitive elements are located in respective first and second photodetector planes. When the objective is correctly focussed and then defocussed in a first direction, the sharpness of the image on the first array increases and that on the other decreases; if the objective is defocussed in the opposite direction, the opposite occurs. A comparator has two outputs, connected to the elements of the first and second arrays via respective first and second circuit branches. Each circuit branch includes at least one subtractor producing an absolute-value output signal independent of the polarity of the difference between the input signals applied thereto. The subtractor inputs are connected to the outputs of respective elements of the respective one of the two arrays. The comparator output signal controls an indication, visible in the camera viewfinder, informing the user of the direction in which he should manually move the focus adjuster to improve the state of focus.

Photographic camera with means indicating the state of focus

A first photodetector arrangement comprises three adjoining photodetectors, and a second comprises six. First and second optics, and the two photodetector arrangements, are located immovable on the camera, and the optics project onto the first arrangement an image of a subject which is to form the basis of a subject-distance measurement, without shift between image and photodetectors of the first arrangement so long as the subject-distance is within one of the ranges the system is to furnish; whereas the image projected onto the second photodetector arrangement shifts relative thereto in dependence upon the distance to the subject. The six photodetectors of the second arrangement are subdivided, for signal-processing purposes, into four successive groups, respectively comprised of the first, second and third photodetector, the second, third and fourth, the third, fourth and fifth, etc. A plurality of comparisons are performed by signal-evaluating circuitry, on the basis of absolute-value versions of the differences between the output signals of individual photodetectors in the first arrangement and in successive photodetector-groups within the second arrangement, to automatically ascertain, sequentially or non-sequentially, which photodetector-group in the second photodetector arrangement is in receipt of an image best corresponding to that cast onto the first photodetector arrangement, thereby determining the subject-distance setting best corresponding to the true subject-distance value.

Focussing system

A focussing system emits an infrared light beam towards the subject, the reflected beam passing through an infrared filter and being projected by a spot optics as a small spot onto a pair of photosensitive elements. The spot optics shifts in a plane normal to the camera's optical axis in dependence upon rotation of the camera's focussing ring, to vary the distribution of the reflected beam onto the two elements, the distribution being equal between them when the state of focus is correct. A circuit derives, from the output signals of the two photosensitive elements, a state-of-focus signal used to automatically focus or else to indicate to the user the direction in which he should manually adjust focus. When focussing is finished, the photosensitive elements are disconnected from the focussing circuitry and connected to the camera's exposure-control circuitry, to thereby serve a dual function. The infrared filter moves out of the light path of the photosensitive elements. The spot optics is moved out of the light path of the photosensitive elements, so that for exposure control a larger light field can be established, or else an auxiliary optics moves into the light path to enlarge the light field in that manner.

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Munich, Germany

Istvan Cocron