JPS61286820A - Focus adjusting device for camera - Google Patents

Abstract

PURPOSE:To make an accurate focus adjustment for various films by switching the 1st and the 2nd modes selectively according to the kind of a film loaded in a camera. CONSTITUTION:A switch OVS is changed over manually according to which of a normal film and a special film is loaded, and when it is connected to a terminal N, the camera corresponds to the normal film and a data output circuit VFD outputs data corresponding to 0 as a quantity of correction. When the switch OVS is connected to a terminal P, the camera corresponds to the special film which is in reverse top/reverse surface relation with the normal film, the data output circuit VFD outputs data corresponding to a quantity d1 of correction. When the switch OVS is connected to a terminal I, the camera corresponds to a thin special film which has a thinner base layer than the normal film and the data output circuit VFD outputs data corresponding to a quantity d2 of correction.

Description

[Detailed description of the invention] Production 1 "JsuL" Su11 The present invention relates to a focus adjustment device for a camera.

I'm confused! Traditionally, in a camera, as shown in Figure 2, the rail surface (2a) of the camera body (2) and the film pressure plate (4)
The lens is configured to regulate the position of the film (F) in the optical axis direction, so that the focus of the photographing lens (L) can be accurately set on the emulsion surface (Fa) of the film (F). That is, as shown enlarged in FIG. 3, the conventional film (F)
When attached to the camera, the emulsion surface (Fa) faces the side facing the photographic lens (L), and the pace (F) faces behind it.
b) is arranged so that

However, recently, unlike the conventional films mentioned above, when mounted on a camera, as shown in Figure 4,
A new type of film (FF) has been announced in which a base (FB) is placed on the side facing the photographic lens (L) and an emulsion surface (FA) is directed behind it. (Polaroid Company: Product name [Borachrome Color Transperancy]) Therefore, when this new type of film is installed in a conventional camera, the emulsion surface is reduced by the thickness of the base (FB). (FA) recedes from the intended imaging plane, making accurate focus adjustment difficult. Furthermore, when controlling exposure by metering the light reflected from the film, such a film (FF
), since the base (FB) is directed toward the photographing lens (L), its reflectance is significantly higher than that of the emulsion surface (FA), resulting in a very large exposure control error.

Also, even in the conventional film (F) as shown in Figure 3, black and white film has a base (F) compared to color film.
Fb) is thin, especially in the case of a black and white film for 72 exposures made by Il 7 Ord. Therefore, the emulsion surface (
Fa) recedes from the expected imaging plane, and the accurate focus [
9E is not guaranteed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a camera focus adjustment device that eliminates the drawbacks caused by various types of films and is capable of accurate focus adjustment even for various types of films.

In order to achieve the above object, the present invention provides a focus adjustment device for a camera that adjusts the focus of a photographic lens, including a focus adjusting means that is moved to adjust the focus of the photographic lens. , a specifying means for specifying the focal position of the photographic lens, a signal output means for outputting a predetermined amount of signal, an eleventh mode, and a second mode.
mode switching means for selectively switching between two modes; when the first mode is selected, a goldfish signal is output when the photographing lens is focused at a designated focusing position; if mode is selected.

The present invention is characterized by comprising a control means for directing the focus of the photographic lens to a position shifted by a predetermined amount from a designated focus position.

LIL
'According to the present invention, by selectively switching between the first mode and the second mode according to the type of film loaded in the camera, accurate focus adjustment according to the type of film is possible. Hereinafter, embodiments of the present invention will be described in detail with reference to FIG.

FIG. 1 is a block diagram showing a camera system to which an embodiment of the present invention is applied. In the figure, a zoom lens is attached to the camera body via a mount member (32). The clutch (34) on the camera body and the clutch (3o) on the lens side are fitted together, and the connector (CNI) on the camera body and the connector (CN3) on the lens side are electrically connected. Inside the zoom lens, a master lens (M L ), a zoom lens (ZL), and a 7-orcus lens (FL) are arranged in order from the object side.
In the illustrated observation state, the light that has passed through these lenses is reflected upward by the main mirror (36) of the camera body, and is brought to a focal point integrated with the condenser lens! (40), passes through a pentaprism (42) and an eyepiece (44) and enters the photographer's clothing. Also, a half mirror is provided on a part or the entire surface of the main mirror (36), and the light that passes through this is reflected downward by the sub mirror (38) and is used for focus detection light receiving part (A F D ) and exposure control. The light is incident on the light receiving section (A ED ).

During exposure of the film (46), the main mirror (36) and sub-mirror (38) are retracted out of the optical path, and the light reflected from the film surface enters the exposure control light receiving unit (AED). Based on the output of the light receiving unit (AED), the amount of light emitted by an electronic flash device, which will be described later, is controlled.

The focus detection light receiving section (A F D ) is composed of a COD, and measures the intensity distribution of incident light. A signal corresponding to the measured light intensity distribution is input to a signal processing circuit (A S P ), and a defocus amount (ΔL1) and a defocus direction are calculated. This detection method is described in, for example, US Patent #j4,
333,007 (Japanese Unexamined Patent Publication No. 57-45510).

The switch (OV S ) is a switch that can be manually switched between normal film and the above-mentioned special film. When connected to the terminal (N), it corresponds to normal film and the data output circuit (VFD ) outputs data corresponding to O as the correction amount. When the switch (OV S ) is connected to the terminal (P), it corresponds to a special film (hereinafter referred to as the first special film) whose front and back sides are opposite to the normal film as shown in Figure 4, and data output is performed. Circuit (V
F D ) outputs data corresponding to the correction @d. When the switch (OV S ) is connected to the terminal (I), it corresponds to a special film (hereinafter referred to as the second special film) whose base layer is thinner than the normal film, and the data output circuit (VFD) Data corresponding to the subsidy return d2 is output. (54) is an addition circuit,
Defocus amount data 1Δ from signal line (60)
L1 and data from the data output circuit (VFD) are added, and if the switch (OV S ) is connected to the terminal (N), the result is 1ΔL1, and if it is connected to the terminal (P), the result is 1ΔL.
l+d,.

(I), data of 1ΔL I+di is output. Each of the correction amounts d1 and d2 corresponds to the deviation from the expected imaging plane relative to the normal film due to the structure of each special film.

(56) is a subtraction circuit, and the data output circuit (
The data from the VFD) is subtracted and the data from the switch (OV S
) is connected to the terminal (N), 1ΔL1, the terminal (
If connected to P), 1ΔL l-d,, terminal (1)
If connected to , data of lΔLl-d2 is output. (DS) is a data selector, and as mentioned above, when using special film, it is necessary to adjust the focus so that the subject is imaged at the rear compared to when using regular film, so The signal line (62) is high at the pin.
h″, the data IΔL l from the adder circuit (54)
+d or 1ΔLl+d2 is the data selector (D
S) is output. Also, the signal line (62
) is "Low''', data lΔLld or 1ΔLl-d from the subtraction circuit (56) is output from the data selector (DS). Note that if the switch (OV S ) is connected to the terminal (N), both the addition circuit (54) and the subtraction circuit (56) are 11ΔL1
Therefore, the defocus amount for normal film is 1Δ
L1 is output from the data selector (DS) regardless of whether it is a front pin or a rear pin.

On the lens side, data corresponding to the focal length set by the zoom ring (ZR) I is stored on the code plate (FC
D), and this data is input to the lens data output circuit (LEC). Lens data output circuit (L
EC) is the line <12 )e (Z3 L (14)
through the lens data reading circuit (LD) on the camera body side.
C) is connected. A signal for activating the lens data output circuit (LEC) when reading data is output from the lens data reading circuit (LDC) to line (12). On line (1,), a clock pulse for the lens data output circuit (LEC) to sequentially output various data one bit at a time is sent to the lens data reading circuit (LD).
C) is output. Line (1,) is a line through which various data are sequentially output one bit at a time from the lens data output circuit (LEC). Furthermore, the line (IlI
) supplies power (VB) to the camera body, and line (1,) is a line that shares the ground between the lens and the camera body.

Line (12) of the lens data output circuit (LEC) is
When it becomes “High”, it enters the operating state, and the line (l,
) and the count value of clock pulses from the code plate (F
Address data is created sequentially based on the data from the CD. This address data sequentially specifies addresses of the ROM in which data regarding various interchangeable lenses are fixedly stored, and the data fixedly stored at the specified addresses are sequentially output based on clock pulses. To convert the defocus amount 1ΔL1 of the data read by the lens data reading circuit (LDC) into the number of pulses from the encoder (ENC) when moving the lens to the in-focus position by rotation of the motor (MO). The lens side coefficient KL is input to a multiplication circuit (50), and the camera body side coefficient KB is input to the other input terminal of this multiplication circuit (50). Therefore, the multiplication circuit (50) calculates KL-KB=KT to calculate the conversion coefficient KT for the entire camera system.

Conversion unit 1 for the entire camera system from the multiplication circuit (50)
1kKT and the defocus amount 1ΔLl, IΔL l+dl, lΔ selected by the data selector (DS)
L l+dx* lΔL I-di, lΔtl-d,
One of the data is input to the multiplication circuit (52), and KT 1ΔLl=PN.

KT・(1ΔL l+d+)=PN.

KT・(1ΔL 1+dt)=PN.

KT・(1ΔL l−cL)=PN.

Perform one calculation from KT・(1ΔL+−dt)=PN to move the 7 orcus lens (FL) to the motor
MO) to calculate the number of pulses PN from the encoder (ENC) necessary for driving to the in-focus position.

The defocusing direction signal from the signal processing circuit (A SP') and the pulse number data PN from the multiplication circuit (52) are input to the motor control circuit (58).

The motor control circuit (58) is a signal processing circuit (ASP
) based on the input direction signal from the motor (M
Determine the rotation direction of O). The rotation of the motor (MO) is transmitted to the clutch (34) via a transmission mechanism (48) including a slip mechanism. The rotation of the clutch (34) is transmitted to the lens-side clutch (30), and the small gear (26) is rotated via the lens-side transmission mechanism (28).

This small tooth ratio (26) is in mesh with the large gear (24) provided on the outer periphery of the focus adjustment member (22), and the small tooth 41 (2
The focus adjustment member (22) is rotated by the rotation of 6). A female helicoid screw is formed on the inner periphery of the focus adjustment member (24), and a male helicoid screw is formed on the outer periphery of the fixing portion (20) integrated with the lens mount member (32) so as to mesh with this. has been done. Therefore, when the focusing member (22) is rotated, this causes 7
The orcus lens (FL) is moved back and forth in the direction of the optical axis to adjust the focus.

Encoder (ENC) according to the rotation of the transmission mechanism (48)
A pulse is output from the motor control circuit (
58). The motor control circuit (58) then counts these pulses, and the count value is calculated by the multiplication circuit (58).
52) When the output data from In the focus adjustment system, a data output circuit (VFD), an addition circuit (54), a subtraction circuit (56)
), data selector (D S ) and changeover switch (O
For a more detailed explanation of the parts excluding V S
This is shown in Publication No. 8.

Next, an exposure control system according to this embodiment will be explained. *The output of the small control light receiving element (AED) is connected to the input terminal of the operational amplifier (OA).
A signal obtained by logarithmically compressing the output current of E D ) with a diode (Dl) is output from the operational amplifier (OA). This photometric output, data Sv corresponding to the film sensitivity used from the film sensitivity data output means (ISD), exposure time data Tv corresponding to the set shutter speed from the exposure data output means (ESD), Aperture value data Av corresponding to the aperture value, open aperture value data A vo
, shutter speed priority mode, aperture priority mode, program, mode, etc., are input to an exposure calculation circuit (ESP) to perform exposure calculation.

Furthermore, a signal indicating the state of charge of the electronic flash device is inputted from the line (f2) to the exposure calculation circuit (ESP).

This signal is "High" when the electronic flash device is fully charged and ready to emit light, and is "Lo" when it is not ready to emit light.
using the various data mentioned above, the line (f2) is
o-", calculations for constant light photography are performed; (when f is 'High', calculations for flash photography are performed; and the calculated exposure control data is displayed on the display
) and the exposure control section (EXC). The display section (D S P ) performs display based on the exposure control data, and the control section (EXC) performs exposure control based on the exposure control data.

Next, the electronic flash device and its light emission control will be explained.

When the electronic flash device is attached to the camera body, the connector (
It is electrically connected to the camera body via CN 5) (CN ff). In the electronic flash device, (BA) is a power supply battery, and (M S ) is a main switch. When the main switch (MS) is turned on, the external voltage circuit (DD) operates and the boosted output voltage causes the diodes (D,
) is charged to the capacitor (C1). (70)
1 is a charging completion detection circuit which outputs a "Low" signal when the charging voltage of the capacitor (C3) is below a predetermined value, and outputs a ``High'' signal when it is above a predetermined value. This signal is input to the 7-nd circuit (ANI), and if the synchronizing contact (SX) on the camera body is open, the “High” signal is output to the line (C2) when the charging voltage exceeds a predetermined value. ) is output.

When the synchro contact (SX) on the camera body is closed, the line (f,) becomes “Low”.
) becomes "High". And the capacitor (
When the charging voltage of C1) exceeds a predetermined value, the output of the 7-nd circuit (ANa) becomes "High''' and 7-rip/70-rub (FF) is set. As a result, the Q output becomes "High", the tri-circuit (72) is operated, the xenon tube (XE) emits light, and the cyrisk (SC) becomes conductive. In addition, 7 lips and 70 tubes (F
When the Q output of F) becomes High'', the timer circuit (
T I ) starts operating, and the dark output becomes "High" for a certain period of time longer than the certain period of time required for the xenon tube (XE) to fully emit light, making the AND circuit (AN) active. Furthermore, when the Q output of the 7-lip/70-tube (FF) becomes High, the output (C2) of the AND circuit (AN,) becomes Low, which transmits to the camera body that light emission has started. be done.

On the other hand, the photometric output output from the operational amplifier (OA) in the camera body is input to the base of the transistor (BT), and is logarithmically expanded to the collector current. Then, the switch (68) turns the line (C2) "Low"'
When it hits 1, it opens, and then the transistor (BT, )
The collector current of is integrated by the capacitor (C2). At this time, the light emitted from the xenon tube (XE), reflected by the subject, and further reflected by the film surface (46) is incident on the light receiving unit (AED), so the condenser (C2) The m-minute output corresponds to the amount of light reflected from the subject by the light emitted from the xenon tube (XE).

Further, data corresponding to the film sensitivity to be used from the film sensitivity data output means (ISD) is converted into an analog signal by a DA converter (DAC), and this analog signal is converted to a collector current by a transistor (B T ). is expanded logarithmically. And the transistor (BT
Resistors (R8) and (R2) are connected to the collector of U), and a linear voltage corresponding to the film sensitivity is output.

By the way, as mentioned above, the first special film is loaded into the camera with the front and back sides reversed from normal film, so the reflectance of the film surface is extremely high (, The other films have substantially the same reflectance, so when the switch (OV S ) is connected to the terminal (P), the changeover switch means (66) is connected to the transistor (BT
, ) and the resistor (R2).
) is input to the comparator (AC),
When the switch (OvS) is connected to a terminal other than the terminal (P), the changeover switch means (66)
A signal from the terminal (MN) connected to the connection point between the resistor (R2) and the resistor (R2) is input to the comparator (AC). Therefore, when the switch (OV S ) is connected to the terminal (P), the amount of light received by the light receiving element (A ED ) will be higher than that of the other terminals (N ) (I
), the output of the comparator (AC) changes from “Low” to “High”.
to be reversed. The signal from the comparator (AC) is sent to the electronic flash device via the line (f,), and if the cannon tube (XE) is emitting light, the 7th ring circuit (ANs> is active, so the 7th ring circuit (A N s)'s exit duck'
The light emission stop circuit (74) is activated and the xenon tube (XE) stops emitting light. Therefore, the reflectance of the film is extremely high compared to other films. Even with the above-mentioned first special film, the amount of flash light emission can be properly controlled using the reflected light from the film.

In this embodiment, a changeover switch (OVS) is provided to accommodate special films, and the switch (0vS) is manually set to a position corresponding to the special film. A signal member indicating that it is a special film is provided on the container for the special film or on the film, so that when the camera detects this, the above-mentioned automatic focus WA adjustment operation and θ light emission amount control operation are automatically switched. Alternatively, in the case of the first special film, by utilizing the fact that the reflectance is extremely different from other films, a means for detecting the reflectance (for example, a photocoupler) is provided, and the reflectance is detected at the end of 11j. The above-mentioned operation may be automatically switched when it is detected that the film thickness is high.Furthermore, means for detecting the film thickness may be provided in the camera body to detect that the film is extremely thicker than normal film. If it is detected that the film is extremely thinner than a normal film, the operation corresponding to the second special film may be performed.

When using a special film in this example, when the lens moves to the in-focus position by automatic focus adjustment, the photographer who is looking through the viewfinder may feel uncomfortable because the lens is focused at the rear with normal film. be. Depending on the switching of the switch (OVS) at the hill, the focus plate (40
) may be moved toward the pentaprism (42) to eliminate the discomfort. Furthermore, if the camera is not equipped with an automatic focus agI device, only the position switching of the focus plate (40) may be provided.

In this embodiment, automatic focus adjustment gtI! Although the present invention has been described above, the present invention can be similarly applied to a device that performs focus detection and displays its state. In the case of this II, the data lΔL1, 1Δ from the data selector (I)
L l+d,, lΔL I+d,, IΔL I-d
If l, IΔLl-d, is smaller than the data corresponding to the focus, the focus is displayed, and if it is larger than the data corresponding to the focus, the front focus or the back focus is displayed according to the signal from the line (62). All you have to do is do this.

Further, in this embodiment, a device that performs an automatic focus adjustment operation based on the amount of defocus has been described, but the present invention can also be applied to an automatic focus adjustment device that uses a device that detects only front focus, in-focus, and rear focus. Applicable. In this case, until the focus signal is output, the lens is driven in the direction based on the front focus or rear focus signal, and when the focus signal is output, the lens is moved by a fixed amount 1 in the retracting direction. , the movement of the lens may be stopped and an in-focus display may be performed.

Furthermore, in this embodiment, two types of special films are supported, but in preparation for when various special films are released in the future, a switch (OVS) with a larger number of positions can be added.
) can be selected, a larger number of focusing positions can be selected accordingly, and it may also be possible to support films whose focal plane is in front of normal films. Similarly, the reflectance of the film may be made to correspond to a larger number of types of reflectance. Alternatively, it may be made to correspond only to the first special film or the second special film, and furthermore, only the reflectance correction corresponds to the first special film, or
Only the automatic focus adjustment device may be corrected.

Furthermore, in this embodiment, the automatic focus adjustment device is provided in the interchangeable lens and extended from the camera body to the interchangeable lens.
Also, the focus detection means detects the focus adjustment state based on the light intensity distribution from the subject that has passed through the photographic lens. Focus detection may be performed based on light that has passed through a different optical system.

Furthermore, there is an automatic focusing system that detects the distance to the subject and moves the photographing lens from its initial position by an amount corresponding to the detected distance signal. Applicable to equipment. In the case of this type of automatic focus adjustment device, when using a special film, the detected distance signal is corrected by a predetermined amount and compared with the lens movement amount signal to determine the lens stop position, or the detected distance signal is The lens stop position may be determined by comparing the distance signal that has been calculated with the lens movement amount signal that has been corrected by a predetermined amount.

Furthermore, the present invention can also be applied to the following devices. First, autofocus i1! ! The first photograph is taken at the lens position adjusted by the adjustment device, then the next photograph is taken by moving the lens a certain amount from that lens position, and the same operation is repeated a certain number of times at high speed.
It is possible to take a fixed number of images at high speed by shifting the lens position by a fixed amount before and after the detected in-focus position. By performing WIII& in this manner, in-focus photography can be performed even with special films having different focus positions, and furthermore, the photographer can select the film with the best focus adjustment state from among a large number of films.

While checking the subject surface focused by the automatic focus adjustment device in the viewfinder, manually adjust the number of steps of the switch (0 S) to increase the number of steps, but finely or continuously, and change it as desired. It is also possible. As a result, for example, in a portrait, it is possible to freely focus on the right eye, left eye, tip of the nose, earrings, etc. while keeping the 7-raming fixed, and it is possible to easily express the sensibility belonging to the photographer. Similarly, when taking close-up shots of a three-dimensional object with a complex fine structure, the focus position can be set at any point in addition to changing the depth of focus.

In this case, data from the data selector (DS) is input for the book that is confirmed to be in focus,
Another data selector is separately provided so that the manually set data 1ΔLMI is input to the multiplication circuit (52) when focus is confirmed, and the motor (MO) is activated by an amount corresponding to this data 1ΔL141. All you have to do is drive it. Regarding the rotation direction of the motor, the differential input direction signal is sent from the terminal (62) until the focus is confirmed, and once the focus is confirmed, the manually set direction signal is sent to the control circuit (58). need to be communicated.

Furthermore, it is also conceivable to introduce the concept of being able to arbitrarily adjust the focusing position into an interchangeable lens barrel. In other words, it is easy to make it possible to set the front focus tendency and the rear focus tendency using adjustment screws according to the preference of the photographer. Conversely, this has the advantage that it is possible to improve the focusing accuracy by making fine adjustments in consideration of manufacturing tolerances at the time of shipment from the factory. In this case, data corresponding to the adjustment amount may be sent to the camera body together with other data as automatic focus adjustment data, this data may be added or subtracted from ΔL, and automatic focus adjustment may be performed based on this data.

Lessons Learned 1fli Union - As detailed above, the present invention provides a focus adjustment device for a camera that adjusts the focus of a photographic lens, including a focus and α adjusting means that is moved to adjust the focus of the photographic lens, and a photographing lens. a designation means for designating a focal position of the lens; a signal output means for outputting a predetermined amount of signal; a mode switching means for selectively switching between a first mode and a second mode; and a first mode is selected. When the camera lens is focused at the specified focus position, a focus signal is output, and when the second mode is selected, the focus signal is output from the specified focus position by a predetermined amount. It is characterized by having a control means for adjusting the focal point of the photographing lens to a position deviated by a certain amount, and by configuring it in this way, it is possible to adjust the focus of the photographing lens according to various films, Excellent focusing accuracy can be guaranteed even when using various films.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a sectional view showing the film positioning lfl structure of the camera, Fig. 3 is an enlarged sectional view showing the conventional film mounting state, and Fig. 4 is a new It is a sectional view showing the mounting state of the announced film. (MO) (34) (48):Focus II Handset 1M, (A
F D )(A S P ): Designation means, (V F
D): Signal output means, (OV S ): Mode switching means, (54) (56) (58) (D S ): Control means. Applicant Minolta Camera Co., Ltd. Figure 2 Figure 3 b Figure 4

Claims (1)

[Claims] A focus adjustment device for a camera that adjusts the focus of a photographic lens, comprising: a focus adjustment means that is moved to adjust the focus of the photographic lens; a designating means for specifying a focal position of the photographic lens; a signal output means for outputting a quantitative signal; a mode switching means for selectively switching between a first mode and a second mode; and a mode switching means for selectively switching between a first mode and a second mode; When the focus of the photographic lens is adjusted, a focus signal is output, and when the second mode is selected, the focus of the photographic lens is adjusted to a position shifted by a predetermined amount from the designated focus position. A focus adjustment device for a camera, characterized in that it has means.