Agfa-gevaert Ag

Kurt Borowski

Istvan Cocron

Theodor Huber

Eduard Wagensonner

Peter Lermann

Gerhard Egger

Otto Stemme

Dieter Engelsmann

Karl Wagner

Gunter Fauth

Richard Wick

Reinhard Nicko

Friedrich Stumpf

August Hell

Josef Ganser

Dieter Knauer

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

When the battery voltage is sufficient, and not nearing the point of insufficiency, a light-emitting diode is steadily illuminated. As the battery voltage decreases, the steady component of illumination decreases and also, when the decrease has proceeded to a certain extent, a superimposed pulsating component of illumination is introduced, causing the illuminated LED to begin to flicker, informing the user that the battery voltage is nearing insufficient values. As battery voltage drops further, the steady component of illumination ceases altogether, and the flicker converts to on-off blinking, indicating that the battery voltage is at the verge of an insufficient value. When the battery voltage drops fruther, the LED ceases to be illuminated. During part or all of the flicker phase, and/or during part or all of the blinking phase, the frequency of the pulsating component of illumination progressively increases with decreasing battery voltage, to create an effect of increasing urgency. In addition, or alternatively, at a certain point during pulsating illumination the frequency of the pulsating component is abruptly increased, likewise to create an effect of urgency.

Circuit for indicating the condition of the battery in a photographic

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

A system is disclosed for automatically controlling the shutter in a camera in accordance with ambient scene light level. While the shutter is opening, incident light is weighted at only one-half the value at which it is weighted after the shutter has been fully opened. A switchable voltage divider is utilized to accomplish the weighting function in accordance with shutter blade position.

Weighting of the scene light signal during the shutter opening operation

Upon exposure initiation, a shutter opens abruptly, an exposure-light diaphragm begins to open progressively, and a control diaphragm, behind whose aperture the light sensor is located, also begins to open progressively. The signal from the light sensor is integrated, and when the requisite total-light amount is reached the shutter falls closed abruptly. Accordingly, the system decides, on its own, what the exposure duration and exposure-light aperture size upon exposure termination will be. The user, however, can modify this fully automatic selection in the sense of longer exposures and smaller aperture, or else shorter exposures and larger aperture, by varying the motion-retarding force supplied by an electromagnetic motion retarder, which controls the speed at which the exposure-light aperture opens up. Prior to exposure initiation, the control aperture is at a minimum, but non-zero size, permitting scene-light-sufficiency measurement. The motion-retarding force is automatically lowered in response to temperature decreases and automatically boosted in response to scene-light increases, to counteract low-temperature slowness of mechanical movements and to prevent the need for unrealizably brief exposure durations. The electromagnetic motion-retarder is not connected to a current source, but instead generates magnetic motion-retarding force in response to movement of inductance-modifying structure in accordance with Lenz' law. When the user wishes to predispose the fully automatic system towards longer or shorter exposure durations or larger or smaller aperture sizes, the light-sufficiency indicator is automatically adjusted to take this into account.

Programmable fully automatic shutter system for photographic cameras

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

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.

Photographic camera with exposure-control and focussing means

An infrared measuring beam is emitted from the camera towards the subject, and reflected back as a tiny light spot projected, by an optics which transversely shifts in dependence upon exposure-objective subject-distance setting, onto one, the other or both of two infrared photodiodes. The signals from the two photodiodes are transmitted in processed form to two output flip-flops through the intermediary of a single, shared signal-processing stage, employing time-division-multiplexed transmission of the two photodiode signals, to assure that the signal processing of the two photodiode output signals be as identical as possible.

Photographic camera with focussing system which time-multiplexes the

When the battery voltage is sufficient, and not nearing the point of insufficiency, a light-emitting diode is steadily illuminated. As the battery voltage decreases, the steady component of illumination decreases and also, when the decrease has proceeded to a certain extent, a superimposed pulsating component of illumination is introduced, causing the illuminated LED to begin to flicker, informing the user that the battery voltage is nearing insufficient values. As battery voltage drops further, the steady component of illumination ceases altogether, and the flicker converts to on-off blinking, indicating that the battery voltage is at the verge of an insufficient value. When the battery voltage drops further, the LED ceases to be illuminated. During part or all of the flicker phase, and/or during part or all of the blinking phase, the frequency of the pulsating component of illumination progressively increases with decreasing battery voltage, to create an effect of increasing urgency. In addition, or alternatively, at a certain point during pulsating illumination the frequency of the pulsating component is abruptly increased, likewise to create an effect of urgency.

Circuit for indicating the condition of the battery in a _photographic

A motion picture camera wherein the diaphragm is adjusted in automatic response to signals from two outputs of a digital comparator which receives a first set of signals during each revolution of the shutter at a frequency varying as a function of changes of shutter speed and of changes of scene brightness. The comparator further receives a set of reference signals from a digital selector circuit during normal operation of the camera or from a binary counter when the camera is set for making exposures with fade-in, fade-out or lap dissolve. The counter forms part of a program circuit.

Motion picture camera

Normally, the negative-feedback diaphragm control system of the motion-picture camera works off a through-the-lens photosensitive element. However, when an image fadeover is to be effected, the lower than normal-operation aperture size commanded for the diaphragm results in a decrease in the light incident on the through-the-lens photosensitive element creating problems if the diaphragm control system is to continue to respond to scene-light changes during the lower than normal-operation aperture-size situation. Accordingly, the through-the-lens photosensitive element is switched out of the control system, and a second photosensitive element is switched in. The second photosensitive element does not operate through-the-lens, but instead is positioned behind an auxiliary light attenuator the front of which is exposed to ambient scene light. The auxiliary light attenuator is coupled to the diaphragm and diaphragm-adjusting motor. When the second photosensitive element is switched in, also switched in is a corrective unit which redefines what the equilibrium state of the negative-feedback diaphragm control system is to be, to take into account the difference in light incident upon the second as opposed to the first photosensitive element.

Altered negative-feedback diaphragm control during implementation of

A light-sensitive element is connected to a capacitor to vary the charging rate of the capacitor in accordance with the light falling on the light-sensitive element. The emitter-collector circuit of a switching transistor is connected in series with the light-sensitive element. The base of the transistor is pulsed by an astable multivibrator which furnishes a pulse sequence having a pulse repetition rate which exceeds the reciprocal of the smallest exposure time. The pulses in the pulse sequence have a pulse width determined by the selected one of a plurality of resistors. The selector switch inserting the selected one of the resistors into the astable multivibrator circuit is coupled to selector means which select one of a plurality of exposure factors as for example the aperture size. The electronic switch is conductive, permitting charging of the capacitor only during the pulse duration. The charging rate of the capacitor can therefore be adapted to the particular aperture size, film sensitivity, etc. without changing the capacitance of the capacitor or covering a portion of the light-sensitive element.

Exposure control circuit

A single light-sensitive element serves to furnish a signal for setting the aperture prior to the exposure time and to control the exposure time. Prior to the exposure time a first and second threshold stage furnish a first and second threshold output signal respectively when the light is in a first and second predetermined range. The first and second threshold output signals are applied to the control input of a first and second D flip-flop. The output of the D flip-flop varies as a function of the signal at the control input only in the presence of a gating signal. The gating signals are applied to the D flip-flops only prior to the exposure time. The outputs of the first and second D flip-flops are applied to an exclusive OR-circuit whose output is applied to aperture control means which vary the size of the aperture in dependence on the logic circuit output signal. The D flip-flop maintains its output after removal of the gating signal thereby maintaining the aperture size during exposure. A switch operative with the diaphragm aperture control switches integrating circuit elements corresponding to the aperture size into the automatic exposure control circuit of the camera during exposure.

Growing community of inventors

Aschheim, Germany

Kurt Borowski