JPH01201633A - Focus correcting device for camera with zoom lens - Google Patents

Abstract

PURPOSE:To correct the shift of focusing caused by fluctuation at every lens by storing the difference to a calculated moving amount generated at the time of assembling a lens or due to the fluctuation of a lens parts dimension, in accordance with every focal distance and bringing a value between plural storage values to interpolating operation. CONSTITUTION:A moving amount from the reference position of a focusing lens is calculated by object distance information obtained from a non-TTL distance measuring means 1 and set focal distance information. On the other hand, the difference to a calculated moving amount generated due to the fluctuation of a lens parts dimension is stored in a storage means 2 in accordance with every focal distance, and when these plural storage values are inputted to an arithmetic means 3, a value between the storage values is brought to interpolating operation by the arithmetic means 3. Subsequently, based on the final moving amount adding the value brought to interpolating operation, to the moving amount from the reference position which has been calculated, the focusing lens is driven by a lens driving means 4. In such a way, the variance of the lens at every camera can be corrected, and also, even when the optical adjustment is shifted, the correction can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is directed to a focus correction device for a camera with a zoom lens, and more specifically, in a camera with a zoom lens that has a non-T T L The present invention relates to a focus correction device that corrects a focus shift due to

[Prior Art] In a camera with a zoom lens that uses an inner focus method for focus adjustment, the rear group lens extends to a different position if the focal length is different even if the subject distance is the same.
The amount of lens extension must be changed according to zooming. Therefore, the applicant has determined the distance at infinity (flash) for each focal length.

The focus 21rir1 device stores each curve of the amount of lens extension at the closest point, and calculates the amount of lens extension from each data of the focal length and subject distance by dividing the distance from flash to the closest point into 64 sections. (Japanese Patent Application No. 128745/1982).

[Problems to be Solved by the Invention] However, in reality, cameras have variations when assembling lenses, or variations in the dimensions of lens parts themselves, so if the calculation result of the above-mentioned extension amount is used as is, In particular, lenses with long focal lengths may result in out-of-focus images.

SUMMARY OF THE INVENTION An object of the present invention is to provide a focus correction device for a camera with a zoom lens, which stores such variations in camera lenses from a reference position for each camera and corrects the amount of lens extension.

[Means and effects for solving the problem] As shown in FIG. 1, the focus correction device for a camera with a zoom lens of the present invention uses subject distance information obtained from the non-T T L all distance means 1 and the set distance information. The amount of movement of the focusing lens from the base or position is calculated based on the focal length information obtained. On the other hand, the plurality of stored values are stored in the storage means 2 corresponding to each focal length, probably due to the difference between the calculated movement amount and the above-mentioned movement amount that occurs during lens assembly or due to variations in lens component dimensions. is input to the calculation means 3, the calculation means 3 interpolates the values between the plurality of ta values. Then, the focusing lens is driven by the lens driving means 4 based on the final moving amount obtained by adding the interpolated value to the calculated moving amount from the reference position.

[Embodiment] The basic system of a zoom lens camera to which the present invention is applied will be explained based on FIG. 2.

The CPU (Central Processing Unit) 11 is composed of a one-chip microcomputer that controls the entire camera, and the basic clock is manually operated by an oscillation circuit 12.
The operation starts by resetting the reset circuit 13. The reset circuit 13 is activated when a battery is inserted and a power switch (not shown) is turned on.

Works by turning off.

E2-PROM14 is in camera state (number of frames is 2, etc.)
This is a non-volatile memory that stores adjustment data (shutter control, lens drive). Therefore, even if the battery is removed, the camera can return to its previous state. Also, E2-
The PROM 14 stores the amount of deviation in the amount of lens extension caused by variations in each lens, as will be described later.

While data is being written to the E2-F ROM 14, the reset operation of the reset circuit 13 is prohibited. E2-
When PROM14 is set to read mode, first the DX code is input from DX terminal 15 to E2-PROM14,
Subsequently, the data is input to the CPU 1l via the serial line. After this, the data is input to the E2-PROM 14, and then to the CPU II via the serial line. Thereafter, the data in the E2-PROM 14 is input to the CPU II.

The AFIC 16 is an AF (autofocus) sensor of the M phase difference method installed at a non-TTL distance measurement position, and its distance data is sent to the CPU II. The auxiliary light lamp 17 is turned on in accordance with this.The EXT terminal 18 is a connection terminal for an external device, and an optional automatic adjuster or the like is connected thereto.

E2-PROM14. AFIC16 and EXT terminal 1
8 is connected to the same serial line and exchanges data with the CPU 11 through serial communication in order to effectively utilize the port of the CPU II.

SWI 9 is a camera operation switch, which includes a release switch, a mode changeover switch, etc. The LED 20 is a light emitting diode located in the viewfinder, and includes a light emitting diode for flash flash warning, focus display, etc. LCD
21 is a liquid crystal display board for displaying the number of frames, camera mode, etc. The IFI C22 is an interface IC having a decoding function for performing photometry in the 11111 destination unit 23 and selecting a motor in the camera according to a command from the CPU II.

M24. M25. M26 are respectively S
ν 2 Yatsuta Motor 1
The winding/rewinding motor and the zoom motor are driven by the decoded signal from the IFIC 22 via the motor driver IC 27. M24 performs lens drive during forward rotation, and performs shutter drive during reverse rotation. When driving the lens, the reset position of the lens is confirmed by the on (open) state of the switch 28, and the control position is confirmed by the number of pulses of the photo ink club 29. When the shutter is driven, the reset position is confirmed when the switch 30 is on, and the aperture control is
This is done by adjusting the pulse width of 24. This adjustment value is stored in R2-PROM14. M
25 winds the film in the forward direction and rewinds the film in the reverse direction. One-frame advance control of the film is performed by counting the number of pulses of the photointerrupter 31. Photo interrupter 29.
31 are turned on only when M 24° M 25 is selected, and the photo ink club output is input to the CPU II via the IFIC 22. The zoom position of M26 can be detected by a zoom encoder 32.

DATEM33 is a date module that imprints data such as the date and 2 hours onto the film, and 5TRB34 is a strobe.

Here, the zoom encoder 32 will be explained. Third
As shown, the zoom encoder 32 is connected to a zoom ring 40.
It consists of a thin film-like conductor pattern that is integrally attached to the outer peripheral surface of the conductor, and a conductive contact piece and a resistor group that are in sliding contact with the conductor pattern. M2
6 (see FIG. 2) rotates, the zoom ring 40 rotates, and a cam (not shown) inside the zoom ring moves the zoom lens back and forth, changing the focal length. Focal length is zoom ring 4
It is obtained by detecting the position of the zoom encoder 32 on 0.

Eight contact pieces T for detecting the position of the zoom encoder 32. -T7 is attached to the fixed frame 41, and is connected to the ground terminal ADoND of the CPU II and the resistor R1, respectively.
, R2, R3, R4° are connected to one end of each of R5, R6, and R7. Note that the value of the above resistance is (R1/R2)−
It is set to be (R3/R)-(R5/R6)-1,67. The other ends of the resistors R1 and R2 are wired together and connected to the A/D conversion Kawabata ADZMA of the CPU 1. The other ends of the resistors R3 and R4 are also connected to each other and connected to the A/D conversion terminal ADZMB of the CPU II, and the other ends of the resistors R5 and R6 are similarly connected to the A/D conversion terminal ADZMC. The other end of resistor R7 is the CPU
Terminal A D to which reference voltage Vrer of II is applied
v. connected to r. This resistor R7 is a protective resistor in case the reference voltage V rcf' is short-circuited to the ground terminal GND.

The conductor pattern of the zoom encoder 32 is shown expanded in FIG. 4(A). A conductive pattern P in which the contact pieces To and T7 at both ends of the eight contact pieces To-T7 are in sliding contact with each other. and R7 are formed of a continuous conductor over the entire zoom area along the circumferential direction of the zoom ring 40, and are supplied with the ground potential GND and the reference voltage Vrcr, respectively.

Pattern P1 of each row in which contact pieces T1 to T6 between them contact
~P6 are each made of a conductor formed in a discontinuous shape in the circumferential direction of the zoom ring 40 as shown. Electrically, the patterns P1 to P6 in each column are partially the conductive pattern P, as shown in the figure.

The electrode pattern Pc (shown with fine diagonal lines on the upper right) is connected to the conductive pattern P7 and applied with the ground potential GND, and the electrode pattern Pv (shown on the right) is connected to the conductive pattern P7 and applied with the reference voltage Vrel'. (shown with rough downward diagonal lines), and an electrode-free part where no electrode pattern is present.

Therefore, when the contact pieces T1 to T6 slide on the patterns P1 to P6 of the zoom encoder 32 as the zoom ring 40 rotates, each of the patterns P1 to T6 slides on the patterns P1 to P6 of the zoom encoder 32, respectively.
~Due to the shape of P6, the contact pieces T1 to T6 are attached to the zoom ring 4.
64 combinations of code signals from the start point 0 to the end point 63 of the zoom encoder position are detected according to the rotational position of 0.

Note that in FIG. 4(A) above, the electrode pattern P c
, Pv, the dotted portion is an auxiliary pattern for preventing malfunction, so basically the electrode pattern in this portion may be removed to form an electrodeless portion.

The 64 code signals of the patterns P1 to P6 read by the contact pieces T1 to T6 are shown in FIG. 4(B). In this code signal table, when the contact pieces T1 to T6 are applied with the reference voltage Vre[', they are "1", and when they are applied with the ground potential GND, they are "0".

Here, if we pay attention only to patterns P1 and R2, these two
4 by reading two patterns on contact pieces T1 and T2.
two states (0,0), (0,1).

(1, 1), (1, O) can be determined, so the A/D conversion terminal AD of CPU II can be determined by the above resistors R1 and R2.
ZMA can determine four levels as shown in the table below.

In other words, the human power applied to the A/D conversion terminal A D ZM by the combined resistance of resistors R1 and R2 is the reference voltage V rc
When l' is 1, R1: R2-1,67, so as shown in the above clothing, 0 to 0.22.0.27
It is divided into four levels: ~0.47.0.52~0.72.0.77~1. Since the A/D conversion Kawabata ADZMA of the CPU II has a high impedance, when one of the patterns P t and P 2 is off, it becomes the level of the other pattern.

'CPUII's other two A/D conversion terminals AD
The configuration related to AD is also the same, and ZMB'
There is ZMC.

Since the zoom encoder 32 has a pattern of six columns, it is possible to detect a total of 64 (0 to 63) encoder positions. Encoder position 1 is the wide (wide-angle) end position, encoder position 60 is the tele (telephoto) end position, and encoder position 63 is the macro position. Encoder positions 61° and 62 are intermediate areas where no photographs can be taken, and encoder position 0 is an out-of-wide position.

As described above, each A/D conversion terminal ADZMA'AD
ZMB that divides the input to AD into 4 levels
' ZMC makes post-processing very easy. That is, the result of A/D conversion is a 6-bit signal in total, of which the upper 2 bits are "00" and "01".

It has already been divided into four levels corresponding to "10" and "11" (binary numbers), so there is no need to newly divide the A/D conversion input into levels. Also, the variation range is very large, so the resistance varies.

Even if there are variations in the base fS voltage V rer, a stable result can always be obtained.

In addition, as shown in FIG. 3, resistors R1 and R2 are connected to each other and connected to the A/D conversion terminal A D ZM of the CPU II.
By suspending the other end connected to the contact piece T1.
Even if both T2 are in contact with the non-electrode portion (OFF), it can be determined as "11" (binary number). Such a configuration has two patterns P1. This helps prevent malfunctions when the distance between P2 is narrow, and also simplifies the configuration of the electrode pattern.

Next, the calculation of the lens extension for autofocus will be explained. Distance data 1 of the reciprocal of the subject distance g
/Ω is given to the CPU 11 from the AFIC 22 as data of 6 integer bits and 6 decimal bits. Since this camera is of an inner focus type, the amount of lens extension (lens extension pulse) S differs depending on the zoom position (focal length) even at the same distance, as shown in FIG. That is, in Fig. 6, the tele end is standard.

Although the curves in each state at the wide end are representatively drawn, the lens is extended according to 60 lens extending curves, each having a different curve from the wide end position 1 to the telephoto end position 60. however,
Since the CPU 11 does not have enough capacity to store all the curves, it stores in the ROM the distance data 1/1 or the lens extension amount S of 20 points from 0 to 20, which is an integer, only for the curve 45 at the telephoto end. ing. The data of this lens extension amount S at the telephoto end is ST.

(j-0 to 20). The curves for each focal length other than the telephoto end are determined by which distance data 1. Q is also on a line that divides internally at a certain ratio, so by multiplying the curve 45 at the tele end by a certain zoom coefficient, the curves for each focal length other than the tele end can be approximately obtained. Therefore, the ROM in the CPU II stores zoom coefficients Cf (i-1 to 60) corresponding to 60 curves, where Cf is the zoom coefficient for each focal length. In other words, the encoder value i of the zoom encoder 32
A zoom coefficient Cf corresponding to is stored in the ROM within the CPU 11.

Therefore, if the zoom ring 40 is operated to set the zoom encoder value l, this set encoder value i
A zoom coefficient Cf corresponding to the value is read out from the ROM. On the other hand, the amount of lens extension at the telephoto end position corresponds to the subject distance measured by APIC16.
read out. Then, based on the lens extension amount at this telephoto end position, calculation is performed in the CPU II using the zoom coefficient Cf, and the lens extension amount at the set zoom encoder value i is determined.

Here, the integer part of the data of AFIC22 is a.

Assuming that the decimal part is b, the feeding amount (feeding pulse) S at the zoom encoder value i can be obtained by the following simple formula.

S-(b (ST, +1-5Ta) +ST l ・Cf, ...... (1) a
1. Such a calculation formula can be calculated satisfactorily even by a 4-bit microcomputer with few calculation instructions. Incidentally, since the curve at the time of macro is completely different from that shown in FIG. 6, the macro curve is specially stored in the CPU 1. The calculation formula is the same as the above formula (1) except that the zoom coefficient Cf is removed.

The above is a case where the zoom lens is as designed, but in reality there are variations for each lens, so the curve shown in Figure 6 will be shifted upward or downward in parallel by the amount of variation. result. Of course, the amount of parallel movement varies depending on the lens, and may vary depending on the telephoto end position,
Even if the amount of deviation is adjusted to O at the wide end position, the amount of deviation will not be 0 at the zoom position between them.
The result will be as shown in the figure. As can be seen from FIG. 7, since the adjustment has been made at the wide end position 1 and the telephoto end position 60, the amount of deviation is zero.

Therefore, in this camera, the above deviation data is stored in the E2-PROM 14 as five data D (k-0 to k-4). This stored data includes at least the lower 4 bits of the A/D converted value, which is a zoom encoder value of 0 (0000) (same as OH1 and below in hexadecimal).
, 16 (10H), 32 (20H), 48 (30
There are 5 data: H), 64 (40H), and each is different. 1 Dl.

D2. D3. Store as D4. However, points with zoom encoder positions of 0 and 64 cannot be measured, so
When measuring, 1 (IH), 16 (IOH), 32
(20H), 48 (30H).

60 (3CH), and from the measurement data D' when the zoom encoder position is at the wide end position 1 and the measurement data D4' when the zoom encoder position is at the tele end position 60,
Find the data DD at point 4. That is, Do and D4 are determined by the 0゛quartic equations (2) and (3).

D-o'-(Dl-Do')/15・(
2) O D -D + (D4'-D3)/12...
(3) Then, based on the stored deviation data of the five points at the zoom encoder position i, the number of deviation pulses at other unstored zoom encoder positions i is determined by interpolation.

Here, the delivery pulse movement *Zs for the zoom encoder value i is obtained as follows.

Zs ・−Dla+ (D(i,+1)−Dia)
Conflict i b - (4) In this equation (4), i
a is an integer value of the upper 2 bits when the zoom encoder value i is expressed in binary, and ib is a decimal value of the lower 4 bits.

The feed-out pulse movement amount Zs in the above equation (4) can also be sufficiently calculated by a 4-bit microcomputer.

According to the above calculation results, the actual payout amount is S+Zs. Furthermore, as is clear from the above equations (2) and (3), even if the adjustment at the tele end position and wide end position is off (even if it is not 0), this can be
14, correction can be performed.

As mentioned above, in this embodiment, first, the APIC16
Obtain the distance information, use that data to search for the lens extension amount data for telephoto mode stored in the CPU II, then obtain the zoom coefficient Cf from the zoom encoder value l, perform calculations within the CPU II, and set the current setting. Find the lens extension amount at the specified focal length. Then, from the zoom encoder value l, the variation data D for each camera is
is read from the E2-PROM14, thereby
The actual lens extension amount is determined by correcting the above-mentioned extension amount.

[Effects of the Invention] As described above, according to the present invention, lens variations among cameras can be corrected, and even when the optical adjustment is incorrect, it can be corrected, etc., and has excellent effects. .

[Brief Description of the Drawings] Fig. 1 is a block diagram for explaining the outline of a focus correction device for a camera with a zoom lens according to the present invention, and Fig. 2 shows a basic system of a zoom lens camera to which the present invention is applied. 3 is an electric circuit diagram showing the configuration of the zoom encoder in FIG. 2, and FIGS. 4(A) and (B) are the encoder patterns on the zoom ring in FIG. 3. Figure 5 is a diagram for explaining the lens extension amount relative to the AF sensor output, Figure 6 is a diagram showing the correction of the lens extension amount relative to the zoom encoder position. It is a line diagram for explaining movement. 1...Non-TTL/l1lI distance means 2...
・Storage means 3... Calculation means 4... Lens drive means

Claims (1)

[Claims] (1) In a camera with a zoom lens that calculates the amount of movement of the focusing lens from the reference position from the subject distance information obtained from a non-TTL distance measurement method and the set focal length information, when assembling the lens or adjusting the lens component dimensions. a storage means for storing the difference between the calculated movement amount and the calculated movement amount caused by the variation for each focal length, a calculation means for interpolating the value between the plurality of stored values, and the calculated movement. A focus correction device for a camera with a zoom lens, comprising: lens driving means for driving the focusing lens based on a final movement amount obtained by adding the interpolated value to the amount of movement.