JP2605293B2 - Zoom camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Industrial application field) The present invention relates to a zoom camera in which a photographing magnification varies depending on a subject distance.

(Prior Art) Conventionally, a camera having a zoom lens system capable of photographing at a fixed magnification has been known.

That is, for example, in an apparatus disclosed in Japanese Patent Application Laid-Open No. 53-113527, an appropriate position of a variable-magnification lens group is calculated and set based on a subject distance and a photographing magnification. This proper position is a position where an image with a constant magnification can be obtained even if the subject distance changes. In Japanese Patent Application Laid-Open No. 55-64204, each rotation angle and scale of the focus ring and the zoom ring are devised so as to obtain a constant magnification, and both rings are integrally rotated. The publication states that such a design is possible if it is preferable that a slight difference in magnification occurs instead of a completely constant magnification, but the specific configuration is not shown.

The above two publications do not disclose the range of constant magnification photographing.

Further, in Japanese Patent Application Laid-Open No. 54-39144, the compensator lens is moved in a predetermined manner different from zooming so that constant magnification photographing can be performed only by zooming operation. Although the publication discloses that the photographing distance D is in the range of 1.5 to 8.8 m and that the magnification is constant, it does not disclose how the photographing distance before and after that corresponds.

Further, in Japanese Patent Publication No. 51-27577, M = f / x (where M is a magnification and x is a subject) so that constant-magnification shooting can be performed only by a focus operation. , And f is the focal length of the zoom lens). The publication describes that the magnification is constant when the photographing distance D is in the range of 2 to 10 m, but does not disclose how the photographing distance before and after that corresponds.

Further, Japanese Patent Application Laid-Open No. 61-38917 discloses an automatic focus (AF) control for controlling f so that f / D is constant.
In this example, the zoom position is controlled to the closest zoom position when the zoom range is exceeded, and a display outside the zoom range is performed.

By the way, zooming is related to the composition of a photographed image, and its quality is evaluated by printing and negative. However, it is generally difficult for a user to determine at which focal length an in-focus subject is to be stopped by a camera viewfinder. Therefore, by setting a focal length having a variable element according to a predetermined program in relation to the distance with respect to the entire photographing distance, and presenting the user with the basics of the composition, it is easy to automate zooming. It is considered that a more appropriate photograph can be obtained by the operation, and as a result, zooming is really easy to use.

(Object of the Invention) The present invention has been made based on the above background, and when zooming in a photographing distance range used in normal photographing, an automatic zoom program operation is obtained, so that it is possible to concentrate on a photo opportunity, and to easily and surely focus on a subject. It is an object of the present invention to provide a zoom camera capable of obtaining a photograph having an appropriate size.

(Constitution of the Invention) The present invention provides a focus lens and a zoom lens,
In a zoom camera having a drive system for driving these lenses, a subject distance detecting means for detecting a distance to a subject, and a shooting magnification for changing and setting a shooting magnification in a predetermined relationship according to the distance to the subject. Setting means; calculating means for calculating a focal length based on output signals from the subject distance detecting means and the photographing magnification means such that the photographing magnification becomes a specific value; and the focal length calculated by the calculating means is a zoom lens. Determining means for determining whether the focal length is within the focal length range, and out-of-range setting means for setting the focal length end of the zoom lens when it is determined that the focal length is not within the focal length range, The drive system is driven by an output from the calculation means or the out-of-range setting means. With this configuration, the focal point of the zoom lens When photographing within the distance range, the photographing magnification changes in a predetermined relationship depending on the subject distance, and when photographing outside the focal length range, the focal length is set at the focal length end of the zoom lens.

(Embodiment) FIG. 1 shows an embodiment of the present invention. In the figure, L _F is the focus lens group, focused from ∞ until recently photographing distance by moving the optical axis. L _Z1 and L _Z2 are zoom lens groups, which change from a short focal length to a long focal length by moving each on the optical axis by a predetermined amount. L _M is fixed by the master lens group, and forms an image of a subject on the film surface F. Focus detection unit 2 the light beam in the pupil position of the photographing lens made by the lens group L _F ~L _M 2 divided by receiving and integration, and outputs the analog data to the microprocessor 1 to digital conversion.

The focus motor drive circuit 3 is a microprocessor 1
Controls the driving of the motor 4 based on the driving rotation amount signal more output, moves the focus lens group L _F in the optical axis direction.
At that time, the encoder 5 monitors the rotation of the motor 4 and outputs a pulse corresponding to the rotation amount to the motor drive circuit 3. The focus motor drive circuit 3 counts the pulses from the encoder 5,
When the count value corresponding to the amount of drive rotation output from is reached, the drive of the motor 4 is stopped. The counter 6 is a motor 4
The number of pulses from the encoder 5 corresponding to the amount of rotation is counted from the photographing lens transfer position (∞), and the count value is output to the microprocessor 1.

The zoom motor drive circuit 7 receives a signal from the microprocessor 1 and controls the drive of the motor 8, and controls the zoom operation unit 9.
Control. The zoom operation unit 9 includes zoom lens units L _Z1 , L
_The zoom lens units _LZ1 and _LZ2 are moved to predetermined positions by moving members such as cams and gears configured together with the holding unit for _Z2 . Further, the zoom operation unit 9 has a brush BR corresponding to the code plate CD. The brush BR and the code plate CD constitute an encoder. This encoder generates a digital code corresponding to the position of the zoom operation unit 9, that is, the focal length of the set photographing lens, and outputs the code to the storage unit 10. . The storage unit 10 is constituted by a ROM, has focal length data at an address corresponding to a digital code, and outputs the data to the microprocessor 1. The storage unit 10 stores other data unique to the photographing lens, for example, the conversion data of the feeding amount (Δd / Δ
L), tele-end focal length data (f _F ), and wide-end focal length data (f _N ).

When the user selects either the normal zoom operation by motor drive or the automatic zoom program operation, the setting unit 11 transmits the mode signal to the microprocessor 1.
Is output to In the normal zoom operation mode,
In response to an operation instruction from a manual operation unit (not shown) in the tele or wide direction, a signal to that effect is output to the zoom motor drive circuit 7 via the microprocessor 1 to drive the motor 8. On the other hand, in the auto-zoom program operation mode, a predetermined operation to be described later is performed in the microprocessor 1 and a signal is output to the zoom motor driving circuit 7 so that the motor 8
Drive control.

Next, input / output data of the microprocessor 1 will be described. First, the operation mode setting unit 11 is detected at the input terminal i _1. That is, the auto zoom program operation mode, and ON the switch setting portion 11, i ₁ = 0, the normal zoom operation mode, i ₁ = 1 signal is inputted from the input terminal i _1. The imaging lens specific data outputted from the storage unit 10, and the focal length set data such as constantly changing data in accordance with the zooming is sequentially input from the input terminal i _2, it is sequentially stored in the memory of the microprocessor 1. Then, in the memory M ₂₁ Δd / ΔL, f _N in memory M _22, f _F the memory M _23, stores a set focal length data f in the memory M _24. Further, the digital data is the focus detection unit 2 is input from the input terminal i _3. In the microprocessor 1 to the data on the basis of calculated defocus amount and its direction, it is further input from the input terminal i _2, calculates a focus drive amount of rotation together with the [Delta] d / [Delta] L that has been stored in the memory M _21. The count value n of the counter 6 is inputted from the input terminal i _4.

The microprocessor 1 calculates the shooting distance D from the count value n. That is, the feeding amount of the lens x ', photographing distance D, the relationship of the focal length f is approximately f ² / D ≒ x' denoted. Here, the count value n of the counter 6 that counts the pulses of the encoder 5 from the taking lens feeding position to the feeding position is generally proportional to the feeding amount x ', where n = ax' (a is a constant). / D = (1 / f ² a) · n holds.

Assuming that a coefficient determined for each photographing lens is k, k / f ² a is data unique to the photographing lens, and thus is stored in the storage unit 10, input to the microprocessor 1 from the input terminal i _2, and stored in the memory M _27. ing. In other words, a microprocessor within 1 calculates a shooting distance D from the above equation by the count value n of the data and the input terminal i ₄ of the memory M _27.
Storing the object distance D to the memory M _40.

Referring to the output data, the program line based on the object distance D stored in the memory M ₄₀ view f _p = f
(D) [with reference to FIG. 2 described later] to calculate the focal length f _p corresponding to and stored in the memory M _10. Is output from the output terminal P ₁ as calculated zoom motor driving rotation amount signal the difference between the focal length f is set to f _p and memory M ₂₄ stored in the memory M _10. The focus motor drive rotation amount signal is output to the driving circuit 3 from the output terminal P _2.

Next, the auto zoom program will be described. FIG. 2 is a graph showing the relationship between the photographing distance (D) and the focal length (f) using the photographing magnification (β) as a parameter. As D and f change on one broken line, the imaging magnification β = f / D becomes constant. Here, the fact that β = f / D holds in the optical system of FIG. 1 will be described with reference to FIG.

_{D = x + 2f F + HH} '+ x' + x "x = f F / β F, x '= - f F β F from _{D = f F / β F +} 2f F + HH'-f F β F + x" = f F (2 + 1 / β _F −β _F ) + HH ′ + x ″ When β <1/10, 2 + 1 / β _F −β _F ≒ 1 / β _F , HH′≪D,
the D = f _F / β F than x "«D.

a _{f = f F β Z, β} = β F β Z from D = f / beta, when the zoom lens, when the photographing magnification is not extremely large, that person, in the normal shooting, such as snap shot, beta = The relationship f / D holds.

In FIG. 3, L _F : focus lens f _F : focal length of focus lens HH ′: distance between principal points of focus lens β _F : magnification of focus lens L _Z : zoom lens L _M : master lens β _Z : zoom Magnification of lens and master lens F, F ': focal length of focus lens A: object point position B: image formation position by focus lens D: distance from object point to film surface (photographing distance) x ": image of focus lens Distance from point to film surface f: Focal length of entire system β: Magnification of entire system

Returning to FIG. 2, the solid line is a program diagram of the present embodiment. The focal length range of the zoom lens is f _F mm on the telephoto side and f _N mm on the wide side. For a subject closer to the shooting distance D _N m, the focal length f _N mm is fixed on the line (second
At the line A) in the figure, the photographing magnification changes greatly. In subjects between the photographing distance D _N -D _F is the focal length changing with relation specific photographing magnification according to the shooting distance. That is, in the photographing distance D _N at the wide end f _N of the near side, the imaging magnification beta _N = f
The _N / D _N, is set to the imaging magnification β _F = f _F / D _F to the far side object distance D _F in the telephoto end f _F of. The relationship between β _N and β _F is β _N ≠
β _F and β _N > β _F. That is, a large object can be photographed on the screen for a near object, and a small image can be photographed for a far object. However, the magnification does not change as the shooting distance changes when the focal length is constant, and changes near the constant magnification. This is a magnification change such that, for example, when photographing a person, the upper body of the person can be photographed on the screen on the near side and the whole body can be photographed on the far side. The line connecting the points of β _N > β _F is B in FIG. Focal length in the object of photographing distance D _F from the far side shooting magnification on the line C is a constant and f _F is greatly changed.

The program diagram f _p = f (D) in FIG. 2 is calculated. When the line B and f _p = mD + n m and n are _{m = (f F -f N)} / (D F -D N) n = (f N D F -f F D N) / (D F -D N _{) βn, β F, D n} , is represented by D _F, m from _{f = βD = (β F D} F -β n D n) / (D F -D n) n = {D n D F (β n −β _F )｝ / (D _F −D _N ) Line A is f _p = f _N , line C is f _p = f _F , and f _p = β _{N DN} , f
a _p = _{β F} D _F.

An example of the internal operation of the microprocessor 1 that executes the automatic zoom program will be described with reference to a flowchart shown in FIG.

# 10 Focus calculation is performed based on the data from the focus detection unit 2. When the focus lens group L _F reaches the in-focus position rotation of the motor 4 is stopped. The count value n from the counter 6 at that time is inputted from the input terminal i _4.

# 15 Determine the zoom operation mode. In the normal zoom operation mode, i ₁ = 1, so the manual signal corresponding to the ON of the tele-direction switch or wide-direction switch of the manual operation unit
Outputs from the P ₂ to the motor driving circuit 3 drives the motor 8 in the direction (# 20, # 25). If i ₁ = 0, enter the auto zoom program operation mode.

# Calculates the photographing distance D in a focus state from the 1 / f ² a counter value n and the input from the input terminal i ₂ photographic lens stored in the memory M ₂₇ inputted from the 30 input terminal i _4. Stores the D of the calculation result in the memory M ₄₀ (# 3
Five).

# D of 40 memory M ₄₀ is, whether corresponding to the focal length of some of the line B of the program diagram of FIG. 2 is calculated from f _P = mD + n, and stores the result of f _P in the memory M ₁₀ Leave (# 4
Five).

# 50 the memory M ₁₀ of f _P a wide Focal length f of the imaging lens which is stored in the memory M ₂₂ is inputted from the input terminal i ₂
Determine if it is greater than _N.

The # 55 f _P if the f _N smaller than f _P and f _N, a memory M ₁₀
Stores the f _N instead of mD + n in (# 60).

# 65 f _P is if greater than f _N, then similarly compared to the telephoto end focal length f _F stored in M _23. f _P is stored the mD + n calculated at # 40 if f _F less than or equal to the memory M ₁₀ as f _P.

If # 70 f _P is greater than f _F, the memory M ₁₀ a f _P and f _F
Stores the f _F instead of mD + n in (# 75).

# 80 # 40 and f _P of # 75 the memory M _10, and the motor from the output terminal P ₁ of the signal of the difference between the set focal length f of the current state input from the input terminal i ₂ is stored in the memory M ₂₄ Output to the drive circuit 7. At that time, signal (M ₁₀ -M ₂₄₎ drives the positive if the motor 8 in the forward i.e. the telephoto direction, negative if the motor 8
Is driven in the wide direction.

# 85 Input terminal i ₂ based on the digital code of the encoder (BR and CD) that changes every moment by the rotation drive of the motor 8
And stored in the memory M ₂₄
Is always determined. # 80 if the difference is not 0
In it continues to output the signal from the _{P 1 (M 10 -M 24)} . When the difference becomes 0, since the setting focal length f becomes a predetermined f _P, and outputs to the motor drive circuit 7 a stop signal of the motor 8 from P ₁ to stop the motor 8 (# 90).

# 95 A series of operations ends in # 10 to # 90, and then i ₁ = 0
Or 1 If i ₁ = 1, the process is in the normal zoom operation mode, so the flow proceeds to # 20. If i ₁ = 0, the flow proceeds to # 10, which is the automatic zoom program operation mode, and the focus detection and focusing operation is performed.

Next, another embodiment of the present invention will be described. Although this embodiment shows those enter the encoder (BR and CD) input terminal i ₂ to set the focal length f of the microprocessor 1 on the basis of the digital code generated from the driving motor 8 sequentially as follows It is also possible to configure. The outputs of the encoders (BR and CD) are input to the motor drive circuit 7 as a monitor. Then, the output terminal P ₁ of the microprocessor ₁
Driving rotation amount corresponding to the difference between f _P of setting the focal length f and the program diagram is output is input to the motor drive circuit 7 is an encoder (BR inputted as the monitor
When the amount of rotation reaches CD), the motor drive circuit 7 stops the rotation of the motor 8. That is, the fourth
Step # 80 in the flowchart of FIG.

Further, in the line B of the program diagram in FIG. 2, in the above description, β _N and β _F can be connected by a straight line.
In the case of a circle, (Da) ² + (fb) ² = r ² , and other parabolic and hyperbolic curves can be considered.

Another program diagram will be described with reference to FIG. In this example, the shooting magnification is increased at the near shooting distance,
Setting the photographing magnification on the far side to be small is the same as the program diagram in FIG. 2, except that the line B in FIG. 2 is divided into segments B1 to B5 and connected. Line B1 is shooting distance D _N
Between -D _1, a constant magnification beta _1, the focal length varies between f _N of f _A.

Segment B2 photographing distance D ₂ -D _3, magnification beta _2, the focal length f _A -f _B segment B3 is photographing distance D ₄ -D _F, magnification beta _3, the focal length f _B -f _c, each The relationship of the magnifications is β ₁ > β ₂ > β ₃ . Line segment B4
Is constant at the focal length f _A between the photographing distances D _{1 and} D ₂ and the magnification is β
It varies between _{1-beta 2.} The shooting distance D ₃ −D ₄ is similarly calculated for the line segment B5.
It is constant and the focal length f _B ratio between changes between the β ₂ -β _3. The program diagram is set as described above.

The configuration for operating the above program is the same as that of FIG. 1, except that the data of f _A and f _B at which the program diagram is switched are input from the storage unit 10 to the terminal i ₂ and stored in the memories M ₂₅ and M ₂₆ respectively. It is remembered. The algorithm in the microprocessor 1 operates according to the flowchart of FIG. Here, # 10 ~
Steps # 35 and # 80 to # 95 are the same as those in the flowchart of FIG. 4, and steps # 40 to # 72 will be described below.

# To D of 40 memory M ₄₀ to determine whether a programmed line diagram of a line A~C throat of FIG. 5, wherein f _P of the line segment B2
= Calculated from beta ₂ D, and stores the f _P in the memory M ₁₀ (# 41).

# 45 f _P of the memory M _10, it is determined whether or exceeds the focal length f _B of the upper limit of the line segment B2, does not exceed f _B, if not exceed, even the lower limit of f _A in addition # 60 f the f _P of _P = beta ₂ D is stored in the memory M _10, the process proceeds to # 80.

# In 46 to # 50 # 45 proceeds to # 46 if it exceeds the upper limit of f _B. Calculates f _P using f _P = β ₃ D line segments B3, determines whether beyond the telephoto end f _F of the interchangeable lens. If it exceeds, since it is on line C, the tele end f _F is increased to f _P at # 51 and # 52.
In advance and stored in the memory M _10, the process proceeds to # 80 as.

In # 55 # 50, if f _P does not exceed the f _F, then subjected to size comparison between f _B, if f _P is greater than f _B D
It means that the corresponding magnification is riding on line B3 proceeds to f _P of f _P = β ₃ D to # 80 as the memory M _10. f _P is f _B
If not, go to # 56.

# 56, since f _P at # 57 # 55 if not greater than f _B, where f _P of f _P = β ₂ D of # 45 is a flowchart of equal or exceeds the f _B, line segments B5 As above
f _P = traveling f _P as f _B in advance # 80 stored in the memory M _10.

# 61 to # 65 # 60 at f _P = β ₂ D of f _P if the f _A smaller, calculates f _P at _{f P = β 1 D (#} 61), the memory M the f _P
10 (# 62), and then the wide end f _{N of the} interchangeable lens
Is determined (step # 65). In this judgment
Since f _P is on f _N is smaller than if the line A, # 66, a f _N of the wide end at # 67 in advance and stored in the memory M ₁₀ as f _P # 8
Go to 0.

# 70 In # 65, if f _P is greater than or equal to f _N ,
Then performs magnitude comparison between f _A, magnification f _P corresponding to D if not greater than f _A advances to # 80 in fact rests on the segment B1.

# 71, since f _P at # 72 # 70 if greater than f _A, where f _P of f _P = β ₂ D a # 60 is a flow in the case f _A smaller, as is on line B4 , F _P = f _A and f _P
Forward to # 80 may be stored in the memory M _10. Steps after # 80 are the same as those in FIG.

(Effects of the Invention) As described above, according to the present invention, in a camera having a zoom lens, a photographing magnification setting unit that changes and sets a photographing magnification in a predetermined relationship according to a subject distance is used. The focal length is calculated from the setting means and the detected subject distance so as to have a specific shooting magnification, and it is determined whether or not the calculated focal length is within the focal length range of the zoom lens. In some cases, the zoom lens is driven to the calculated focal length.On the other hand, when it is determined that the focal length is not within the range, the focal length is set to the focal length end of the zoom lens to drive the zoom lens. When shooting in the normal shooting distance range, automatic zooming with an appropriate shooting magnification according to the subject distance is possible, making it easy to take pictures with the appropriate size of the subject on the screen Shadows can be cast, which is particularly suitable for snapshot photography and portrait photography. Also, with the automation of zooming, the user can concentrate on the photo opportunity. Also, when photographing on the near side or far side outside the focal length range of the zoom lens, it is possible to photograph at the wide end and the tele end of the zoom lens.

In addition, by setting the shooting magnification when shooting a short-distance subject larger than that when shooting a short-distance subject, beginner users' shooting intentions are further enhanced.
It is strongly reflected, and can contribute to improvement of usability.

[Brief description of the drawings]

FIG. 1 is a block diagram of a zoom camera according to one embodiment of the present invention, FIG. 2 is a program diagram of a photographing magnification according to a photographing distance and a focal length in one embodiment of the present invention, and FIG. FIG. 4 is a diagram of an optical system for explaining the principle, FIG. 4 is a flowchart for executing an automatic zoom program, FIG. 5 is a program diagram for another embodiment, and FIG. 6 is a program for executing the program of FIG. It is a flowchart for performing. L _F … focus lens group, L _Z1 , L _Z2 … zoom lens group, 1… microprocessor, 2… focus detection unit, 3
…… Focus motor drive circuit, 4 …… Motor, 5 ……
Encoder, 6 ... Counter, 9 ... Zoom operation unit, B
R, CD ... Encoder, 10 ... Storage unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takanobu Ohmaki 2-30 Azuchicho, Higashi-ku, Osaka-shi, Osaka Inside Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Takehiro Kato 2-chome, Azuchi-cho, Higashi-ku, Osaka, Osaka 30 Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Yukio Maekawa 2-30 Azuchicho, Higashi-ku, Osaka-shi, Osaka Osaka International Building Minolta Camera Co., Ltd.

Claims (2)

(57) [Claims] A focus lens and a zoom lens;
In a zoom camera having a drive system for driving these lenses, a subject distance detecting means for detecting a distance to a subject, and a shooting magnification for changing and setting a shooting magnification in a predetermined relationship according to the distance to the subject. Setting means; calculating means for calculating a focal length based on output signals from the subject distance detecting means and the shooting magnification setting means such that the shooting magnification becomes a specific value; and a focal length calculated by the calculating means is a zoom lens. Determining means for determining whether the focal length is within the focal length range of the zoom lens, and out-of-range setting means for setting the zoom lens to a focal length end when the determining means determines that the focal length is not within the focal length range. A zoom camera, wherein the drive system is driven by an output from the calculation means or the out-of-range setting means. 2. The photographing magnification set by the photographing magnification setting means is set by a function in which the photographing magnification of a short-distance object is larger than that of a long-distance object, and the out-of-range setting means is a zoom lens when the photographing magnification is large. 2. The zoom camera according to claim 1, wherein the zoom end is set at the telephoto end of the zoom lens when the photographing magnification is small.