DE3150284C2 - Exposure control device in a photographic camera - Google Patents

Abstract

Electrically or optically tactile elements are optionally provided at predetermined first to fifth display locations on a photographic film magazine. The tactile elements provided in the first to fifth display positions represent multipliers of 2x, 4x, 16x, 2 ↑ 1 ↑ / ↑ 3x or 2 ↑ 2 ↑ / ↑ 3x. The sensitivity of the film contained in the magazine is determined by multiplying a predetermined sensitivity standard value given by the multiplier (s) represented by the elements present. If the sensitivity of the film contained in the magazine is normal, no tactile elements will be provided in any of the locations. Sensitivity-sensing elements on a camera may be capable of either sensing the tactile elements in all of the first through fifth locations, or capable of sensing the tactile elements in only the first through third locations. In the latter case, the exposure is controlled based on a sensitivity a notch or two lower than the precise sensitivity of the film contained in the magazine.

Description

Table 1 (continued)

Film speed Ad spot 3 4th 5 (ISO) 1 2 Multiplier χ 16 x2 "3 x2 x4

I. 1600 25x4x16 0 0 0 2000 25x4x16x2 · « 0 0 0 S. 2500 25x4xl6x2 ^M. 0 0 0 i . 3200 25x2x4x16 0 0 ί 4000 25x2x4xl6x2 "3 0 0 5000 25x2x4xl6x2 ^2/3 0 0

In Table 1, the sensitivity of ISO 1600 is indicated by providing the tactile elements in the second and third display positions, ie 25x4χ 16. However, ISO 1600 can be increased by providing the tactile elements in the first, third, fourth and fifth display positions, ie 25 × 2 χ 16 χ 2 ^1/3 χ 2 ² ^, be displayed. In the same way, ISO 100 can be displayed by providing the tactile elements in the first, fourth and fifth display positions, ie 25 χ 2 χ 2 ^{I / 3} χ 2 ² ^, instead of arranging the tactile elements only in the front display positions, such as in Table 1. However, it is preferred to use the smallest possible number of display parts.

The tactile elements can be felt either optically or electrically.

The sensitivity sensing system to be provided on the camera side preferably has five sensing elements which each feel whether or not the first to fifth display position on the housing of the in the camera inserted magazine is provided with tactile elements.

However, the sensitivity sensing system may have only three sensing elements for sensing whether the first to fifth display positions are equipped with tactile elements or not. In the latter case, the fourth and fifth digits, which are multipliers of 2 ^1/3 χ and 2 ^ ³ χ, are not taken into account, and no sensing is performed as to whether or not they are provided with tactile elements. Therefore, a sensitivity indicated by using the fourth or fifth digit is read as a sensitivity given by dividing the exact sensitivity ^{value by 2 "3} or 2 ^M That is, the exposure becomes one or two degrees due to a sensitivity is lower than the exact speed of the film in the cassette, so that the film is overexposed by a step or two, but in practice, overexposure by a step or two causes almost no problem.

Generally, a high quality camera will be provided with a sensory sensing system that includes five sensing elements to perform accurate reading of the sensitivity indicator has to be equipped while an inexpensive Camera model with a sensitivity sensor system that only has three sensor elements to guide through rough reading of the sensitivity display has to be equipped, reducing the manufacturing cost be reduced.

Therefore, it is preferred that the first to third display sites are arranged close to each other and the fourth and fifth display positions are arranged adjacent to the first to third display positions so that the film magazine easily with both the sensitivity sensing system with five sensing elements and the one with only three sensing elements can work together.

The invention is explained in more detail below with reference to the accompanying drawings. It shows

F1 g. 1 is a side view of a film magazine according to an embodiment of the invention;

F i g. 2 is a fragmentary sectional view taken along line H-II of FIG. 1;

F i g. 3 is a view explaining an example of a sensitivity sensing system to be used with the film magazine of FIG Invention, in which the fillable elements can be felt optically, can work together;

F i g. Fig. 4 is a circuit diagram showing an example of an exposure control system to be used with the film cassette of the invention can work together;

F i g. FIG. 5 is a view explaining an example of a sensitivity feed system associated with the film magazine of FIG Invention in which the tactile elements can be felt electrically, can interact, and

F i g. Fig. 6 is a view explaining another example of a sensitivity sensing system incorporated with the film magazine the invention, in which the tactile elements can be felt electrically, can interact.

F i g. Fig. 1 shows a film magazine according to an embodiment of the invention applied to a magazine for a 35 mm roll film. The film magazine 10 has a cylindrical body 11 with a slot 12 through which the roll film contained in the housing 11 is removed. On one side of the slot 12, the housing 11 has one to five display points 1 to 5, in which an optically tactile element is provided selectively or in a selection depending on the sensitivity of the film contained therein. The optically tactile elements in the first to fifth Display position 1 to 5 are arranged, represent multipliers van 2 χ, 4 χ, 16 χ, 2 ^{1 / J} χ or 2 ^V3 χ. That is, if the tactile element is arranged in the first position 1, the sensitivity of the The film contained in the case 11 is given by multiplying a predetermined norm or standard value by two. Assuming the normal value is ISO 25, then the sensitivity of the film is ISO 50 (25 χ 2). If more than one place is provided with tactile elements, the sensitivity of the film is given by multiplying the standard value by all the multipliers represented by the display positions provided with the tactile elements. In FIG. 1 specific embodiment shown

a tactile element is only provided in the second position 2, as shown by hatching. Accordingly, the sensitivity of the film contained in the case 11 is determined by multiplying the standard value by 4, d. H. 25 χ 4 = 100 (assuming the standard value is ISO 25).

The housing 11 is made of sheet metal 13 with a colored layer 14 of a coated thereon. suitable resin as shown in Fig.2. The optically tactile element is removed by removing the Paint layer 14 to expose the surface of the metal sheet 13, which has high reflectivity, is created.

The sensitivity display provided on the case 11 can be read by feeling the reflectivity of the first to fifth display digits 1 to 5 on the case 11, respectively. F i g. 3 shows an example of a sensitivity sensing system to be switched on the camera side. When the magazine 10 is inserted into the camera, the first through fifth display positions of the housing 11 are exposed to light from a light source, such as a light emitting diode, provided in the camera housing. The sensitivity sensing system includes first to fifth light sensing elements D 1 to D5 which are arranged to receive reflected light from the first to fifth display positions 1 to 5. on.

The first to fifth light sensing elements D 1 to D 5 are connected in series with first to fifth resistors R 1 to R 5. The combinations of the light sensing element and the resistor are connected between terminals X and Y in parallel with each other. The light sensing elements Di through D 5 conduct on receiving light and establish an electrical circuit through each light sensing element and the associated resistance between terminals X and Y. In this way, the combined resistance between terminals X and Y varies depending on which Positions in the first to fifth display positions have high reflectivity. That is, the value of an electric current flowing between the terminals X and Y changes depending on the sensitivity of the film contained in the magazine.

Each light film element is normally in a non-conductive state and is placed in a conductive state to establish the circuit through the light sensing element itself and the associated resistance between terminals X and Y as it reflects off the high reflectivity metal surface that serves as the sensible elements Light receives. It is not necessary that the light sensing element be a single element. The light sensing element may comprise, for example, a combination of a phototransistor and an amplifier or a combination of a phototransistor and a relay.

In the above embodiment, the tactile elements on the magazine housing are removed by removing them of the paint layer 14 to expose the high reflectivity metal surface is created. However The tactile elements can be in the form of an area with one of the color of the remaining part of the Magazine surface different color can be created. In this case a Filters arranged to spectroscopically feel the tactile elements.

Referring to FIG. Fig. 4 becomes an example of a diaphragm priority exposure control system having a sensitivity sensing device similar to that in FIG. 3 is used, described in detail below.

In Fig. 4 comprises a light measuring circuit A a photosensor A 1, the resistance of which depends on the

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A film sensitivity sensing circuit B similar to that of FIG. 3 includes first to fifth resistors RA to RE and first to fifth photoelectric switches SA to SE connected in series with the first to fifth resistors RA to RE , respectively, the combinations of resistors and photoelectric switches in parallel with one another constant voltage energy source £ are connected. Each of the photoelectric switches SA to SE is closed when an associated sensing element receives light reflected by an area of the surface of the magazine housing with high reflectivity serving as the tactile elements, and is otherwise open.

The resistances of the resistors RA to RE are selected to have the following relationship with each other. The resistors RA to RE form a resistor network, the total resistance of which changes depending on a digitally coded film sensitivity as shown in Table 2

RB = 1/2 RA, RC = 1/4 RA, RD = 3 RA, RE = 3/2 RA.

The amount of electrical current flowing through the resistor network represented by the first to fifth resistors RA to RA changes with the total resistance of the network, ie changes depending on which one or more photoelectric switches are closed and that through the network

Electric current flowing is fed into the monitoring circuit D as the sensitivity signal SG 2 (Sv)

An aperture value information circuit C feeds aperture value signals SG 3, which represent the aperture, into the control circuit D. The control circuit D calculates the exposure time (Tv) (Tv = Bv + Sv-A v) on the basis of the brightness signal SG 1, the sensitivity signal SG 2, and the aperture value signal SG 3 and controls the shutter mechanism.

When a camera with the exposure control system shown in Fig. 4 is loaded with a film magazine that contains a roll film with a sensitivity of ISO 100 and correspondingly carries a highly reflective area in the second display position, the second photoelectric switch SB is closed to switch on to establish the second resistor RB . Thus the amount of the through the resistor network,

to get into the monitoring circuit as the Ernpfindüchkeiissigua! SG 2 to be fed, flowing electric current IE / RB = E / i / 2RA = 2xE / RA, in the relationship between the resistors RA to RE v / 'ie described above. In the same way, if the magazine contains a roll film with a sensitivity of ISO 200 and correspondingly highly reflective areas in the first and second display positions 1 and 2

carries, the photoelectric switches SA and SB are closed and accordingly the amount of the current is E / RB + E / RA * = 2xE / RA + E / RA * = 3xE / RA. The amounts of the current flowing through the resistor network corresponding to film sensitivities from ISO 25 to ISO 1600 are shown in Table 2, in which the amount of current flowing through the network when only the first resistor RA is connected to the energy source E is represented by / o, ie E / RA = Iq.

Table 2

Film speed ^ current (I)

25 0

32 V ₃ 1 ₀

40 V ₃ Io

50 1 / o

64 IV ₃ 1 ₀

80 IV ₃ k

100 2 1 ₀

125 2V ₃ / o

160 2 _^2/3 1 ₀

200 3 I ₀

250 3V ₃ / o

320 3V ₃ I ₀

400 4 I ₀

500 4V ₃ 1 ₀

640 4V ₃ / o

800 5 1 ₀

1000 5V ₃ 1 ₀

1250 5V ₃ 1 ₀

1600 6 1 ₀

As can be seen from Table 2, the amount of current increases twice every time the sensitivity increases of the film increased by twice That is, the current / is proportional to the logarithm of the sensitivity This is represented by the following formula:

By feeding in the heat signal and the bicilderivvcrisignäis as well as the sensitivity signal

logarithmic values, the operation in the control circuit can be easily performed with high accuracy will. The exposure time is given as a logarithmic value in the working circuit of the control circuit calculated and then the logarithmic value is converted into an anti-logarithm, with its value the locking mechanism is controlled, converted.

In the one shown in FIG. 4, the sensitivity of the film is considered to be ISO 25, if there are no tactile elements in any of the display positions 1 to 5 of the camera inserted Magazine are provided, even if the magazine does not carry the sensitivity indicator according to the invention. To adapt the system to magazines that do not have a film sensitivity indicator according to the invention, the system can be equipped with facilities for changing the resistance of the resistor network by hand or for Set the camera to film speed by hand. For example, a mutable Resistor must be connected in parallel to the resistor network. It is also desirable to have a facility to provide for generating a warning signal when there is no tactile element in any of the first through fifth Display points is arranged

Referring to FIG. 5 shows another embodiment of the invention in which the tactile elements are in the form of electrical contacts. In this embodiment, the first to fifth display positions on the magazine housing are optionally provided with an electrical contact and the electrical contacts provided in the first to fifth display positions la to 5a represent multipliers of 2x, 4x, 16x, 2 ^{l / 3} x and 2 ^M χ The electrical contact is made at the required location by removing the insulating layer on the magazine housing to remove its conductive metal layer in a manner similar to that shown with regard to FIG. 2 described to expose. A common contact 6 is provided adjacent to the display points la to 5a by removing the insulating layer of the magazine housing. In this way, the electrical contact created in each of the positions la to 5a is electrically connected to the common contact 6 through the metal layer of the magazine housing. The sensitivity sensing device to be provided in a camera has first to sixth sensing contact pins 21 to 26 which are brought into contact with the first to fifth display points 1 a to 5 a or the common contact 6. The sixth contact pin 26 is connected to a constant voltage power source 27, the first to third contact pins 21 to 23 are connected to a first D / A converter 28, and the fourth and fifth contact pins 24 and 25 are connected to a second D / A converter 23 connected. The outputs Vi and Vz of the first and second converters 28 and 29 are added by an adder 39 and the sum is fed to the exposure control circuit (not shown in FIG. 5) as the film speed signal SG 2 (Sv). A converter is set to be 1/3 the gain of the first D / A converter 28 Die

The relationship between the output V \ of the first converter 28 and the sensitivity display on the magazine case is shown in Table 3, and the relationship between the output Vj of the second converter 29 and the sensitivity display is shown in Table 4.

Table 3

ISO la 5a 2a 3a Analog Vi 0 V ₂ 0 value 1 V ₀ 0 25th 0 1 0 0 0 2 V ₀ 1 χ 1/3 V ₀ 50 1 0 0 0 1 3 V ₀ 2x1 / 3 V ₀ 100 0 1 1 0 2 4 V ₀ 3x1 / 3 V ₀ 200 1 1 0 3 5 V ₀ 400 0 0 1 4th 6 V ₀ 800 1 0 1 5 7 V ₀ 1600 0 1 1 6th 3200 1 1 1 7th Table 4 4a Analog value 0 0 0 1 1 2 1 3

F i g. Figure 6 shows another example of the sensing system that can be used when the tactile elements are electrically tactile. The sensing system of this example has first to sixth contact pins 21 'to 26' which are intended to be attached to the magazine housing in contact with the first to fifth display points la to 5a or the common contact 6. The first to fifth contact pins 21 'to 25' are connected to first to fifth resistors RV to R 5 'of different resistance, and the combinations of the contact pins and the resistors are connected to a terminal Y in parallel with each other. The sixth contact pin 26 'is connected directly to a terminal X. A sixth resistor R 6 for the standard sensitivity is connected between the connections X and V. Since the resistance values of the first to fifth resistors differ from one another, the total resistance between the outputs X and Y changes depending on which position or positions is or are conductive, ie are provided with electrically perceptible elements. Accordingly, the sensitivity display on the magazine housing can be sensed as the electric current flowing between the outputs X and K. When none of the first to fifth display positions la to 5a is conductive, electric current flows only through the sixth resistor R 6, and then the sensitivity of the film is regarded as the standard value, e.g. B. ISO 25, regardless of whether the magazine carries a sensitivity indicator encoded according to the invention. This can be done by means of variable resistors, which can be connected between the outputs X and Y instead of the sixth resistor R 6 or between the outputs X and Y, to be changed manually, for which the resistors R Γ to RS ' and ^r R 6 having resistor network. Further it is desirable. Means for generating a warning signal if none of the first to fifth display positions is conductive to be provided.

It is preferred that the contact, which is optionally present in the first to fifth display positions, has high reflectivity, which means that the magazine is either connected to a camera with a sensitivity • sensing system, that feels the sensitivity optically, or with a camera with a sensitivity-sensing system, that feels the sensitivity electrically, can work together.

Further in the in F i g. 5 and 6 shown embodiments of the common contact 6 for electrical Sensing whether the first to fifth display digits are electrically conductive or not is used. However, the common contact can be omitted when using a pair of contact pins for each display position.

Further, the above-described examples of the sensitivity sensing system have first to fifth sensing elements, that is, the first to fifth light sensing elements D 1 to DS or the first to fifth contact pins 21 to 25. However, the fourth and fifth sensing elements can be omitted if the film sensitivity indicator on the cassette is not must be read exactly as described above.

In the ISO sensitivity system, sensitivities are expressed either in arithmetic values or in logarithmic values. In the former case, sensitivities are represented by the same values as in conventional ASA sensitivity system, while in the latter case sensitivities are shown by the same values are displayed as in the conventional DIN sensitivity system. In the above In the description, the invention has been described on the basis of arithmetic values of the sensitivities. However in the case that the sensitivities by logarithmic values, where sensitivity values are in an arithmetic As the progressive sequence change, the multipliers should be used in the description above as

Differences are read.

For this purpose 2 sheets of drawings

Claims (2)

Patent claims: 1. Exposure control device in a photographic camera, with a sensing device for sensing a film speed marking in binary coded form on a film magazine inserted in the camera, which has at least 5 code digits, and with a decoder, through whose output signals the exposure can be controlled according to the film speed, characterized in that the decoder (R i -R 5) is constructed in such a way that it assigns a multiplier to each code position (1 ... 5; la ... 5a, 6), each multiplier having a single basic value for the film speed is multiplied. 2. Exposure control device according to claim 1, characterized in that the first, second ... fifth code position the multipliers 2, 4, 16, 2 ^m and 2 ^{m are} assigned, and that the basic value 25 (ISO) transmits The invention relates to an exposure control device in a photographic camera according to the preamble of claim 1. Various types of film containers have been developed to go along with that contained therein Film can be inserted into the fCimera. The containers have e.g. B. the form of film magazines, cassettes or cartridges,! In the following, such containers will be referred to with the expression »film magazine. In photographic cameras with automatic exposure control devices, it is desirable to have the automatically adjust the respective film speed of the inserted film, so that a corresponding, of Adjustment process to be carried out manually can be dispensed with. In DE-OS 25 34 516 there is an exposure control device of the type mentioned above, in which the decoder film speeds between ASA 16 and ASA 1000 can decode. The gradation is here 16,32,40,50 ... The well-known decoder is designed such that when, for. B. Film speeds of ASA 25, 250 or 500 can be decoded an additional code must be provided. Then it is not just necessary to put the coding on to change the film magazine, but also in the camera the decoder must be designed accordingly will. This naturally makes the camera more expensive. The invention is based on the object of providing an exposure control device of the type mentioned at the beginning to develop in such a way that despite a simply constructed decoder and a correspondingly designed Film sensitivity marking on the film magazine covers a large sensitivity range. This object is achieved by the invention specified in claim 1. The multipliers 2, 4, 16, 2 ¹ · · and 2 ² ^ respectively are assigned to the codes, while the basic value is 25. Table 1 below illustrates the basic principle of the invention Exposure control device in connection with the film speed mark. If you z. For example, assuming that the predetermined basic value of the film speed is ISO 25 and the multipliers "2" and 2 ^{[n are} assigned to the first and fourth code positions, the result is a value of 25 if the film speed rating is coded accordingly on the film magazine χ 2 χ 2 ^{l / 3} = 64. If the film speed marking on the film magazine causes the encoder to respond in the second code position, if this code position is assigned the multiplier »4«, the film sensitivity is ISO 100. Table 1 Film speed 25x1 advertisement -Job Multiplier x4 3 (ISO) 25 χ 2 " ³ 1 2 x2 25 χ 2 ^2/1 > 25x2 25th 25 χ 2 χ 2 " ³ 32 25 χ 2 χ 2 ² ^ 0 40 25x4 0 50 25x4x2 " ³ 0 0 64 25 χ 4 χ 2 ^m 0 SO 25x2x4 0 100 25x2x4x2 '" 0 125 25x2x4x2 ^2/3 0 0 160 25x16 0 0 200 25x16x2 " ³ 0 250 25 χ 16 χ 2 ² ' ³ 320 25x2x16 0 400 25x2xl6x2 " ³ 0 500 25x2xl6x2 ^2/3 0 0 640 0 0 800 0 0 1000 0 1250