DE3003605A1 - DEVICE FOR THE ELECTRICAL TRANSMISSION OF LENS INFORMATION - Google Patents

Description

PENTACON DRESDEN Dresden, January 17th, 1980 Camera and Klnowsrki 044

Device for the electrical transmission of lens information

The invention relates to a device for the electrical transmission of lens information into the automatic program photographic cameras in which the exposure setting is controlled by a central processing unit will"

With cameras of this type it is necessary to have information about the boundary conditions under which a recording is made should, to give to the central processing unit · So is already known from the lens by means of electrical Means the preselection required for automatic timing the aperture size in the camera (DD-PS 110 336) < It was also proposed that the respective distance setting of the lens, its aperture range as well as its focal length electrically into a central processing unit controlling the exposure and focusing to be entered (DD-WP 206 096) ♦

Each of these information transfers require a separate transmission line. As part of the standardized Lens manufacture, however, prohibits any change in the electrical connection parameters.

Hit the invention is the input of lens information can be simplified into the automatic exposure control

The object of the invention is to provide a device for the electrical transmission of a plurality of lens information by means of a common transmission channel, whereby the individual parameters do not influence each other

should·

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According to the invention this object is achieved in ₀ that shown in the circuit of each set aperture size or aperture area simulating electrical "actuator A coupled with the distance setting variable resistor or ₀ a Ob is gen" jektivbrennweite simulating switching element einbeao = and that different electrical characteristics of said Objective circuit is transferred to the camera via lens-side connection elements connected to the first-mentioned actuator ₉ measured in an evaluation circuit in time-division multiplex operation and fed to the program = automatic known resistance attenuator, an adjustable resistor is switched and the parameters measured in time-division multiplexing are set by the no-load voltage attenuation characterizing the respective aperture and by the te distance characteristic no-load output resistance of the lens circuit formed

The invention is explained below using an illustrated embodiment:

In an objective 1 is a resistance attenuator 2, which is constructed like a high-frequency voltage divider and has a constant input and output resistance, arranged, whose grinder 3 is coupled to an aperture setting ring 4-. The electrodes of the resistance attenuator 2 are connected to connecting elements 5 »6» 7 arranged on the camera side of the lens · Between the connection element 7 and the slider 3 is an adjustable resistor 8 is connected, the tap 9 of which is coupled to a distance setting ring 10 is · Said connection elements are marked with the corresponding

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Contact surfaces 11, 12, 13 of a camera housing 14 in connection · The mentioned contact surfaces form the entrances an evaluation circuit 15, the outputs 16 of which are fed to an automatic exposure circuit 18.

The mode of action is as follows:

manual or automatic aperture and distance setting using the aperture setting ring 4 or » Distance setting ring 10 determines the evaluation circuit 15 in time division multiplexing two electrical parameters the lens circuit formed by the resistance attenuator 2 and the adjustable resistor 8 On the one hand, the no-load voltage damping is achieved via the contact surfaces 11, 12, 13

at I ₁₁ - O ^U 11, 12 ^ΊΊ

measured · This value characterizes the respective on the lens 1 set aperture size · After transmission of this electrical parameter in z · B «binary coded form in the arithmetic unit of the automatic program 18 is on the other hand via the same signal line (contact surfaces 11, 12) of the Open circuit output resistance

W -

measured «This value characterizes the respective

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sr 5

set recording distance; it is also entered in the automatic program circuit 18 for further processing transferred · The size of A determines the necessary exposure time and the reported size of W denotes e.g. B «an optimal focusing has taken place of the lens or provides a correction variable for the focus setting which is entered into the arithmetic unit or for the initially determined combination of aperture sizes and exposure time. For electrical Transfer of aperture sizes and distance settings all that is needed is a common transmission channel from the lens to the camera «,

In the manner described above, the diaphragm area of an objective on the one hand as well as its Focal length on the other hand in the automatic program transmitted to a camera

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Claims (1)

Claims s 1 »device for electrical transmission of Ob = jektivinformationen in the program = automatic photographic cameras _p characterized _ΰ that in the circuit of the respectively = presented aperture size or aperture area simulating the electric actuator (2) coupled with the distance collar a" Adjustable-Y / resistance (8) or «, a switching element simulating the lens focal length is included and that different electrical parameters of said lens circuit via lens-side connection elements (5 _S 6 ₀ 7) connected to the first-mentioned actuator in the camera (4 ) transmitted ^ measured in an evaluation circuit (15) in time multiplex mode and fed to the automatic program (18) who Device according to Claim 1 _8, characterized in that an adjustable resistor (8) is connected in series with a wiper (3) of a known resistance-attenuator (2) coupled to the diaphragm _{adjustment ring, and that the parameters measured in time = multiplex mode are from the} the idle speed characterizing the respective aperture opening = voltage damping as well as from which the idle speed characterizing the set distance the output resistance of the lens circuit is formed © 3. Device according to claim I _9, characterized _{in that the output signals of} the evaluation circuit are binary coded 0300A0 / 0604 BATH ORIGINAL