JPH01287510A - Interchangeable lens camera - Google Patents

Abstract

PURPOSE:To perform rational operation even when a lens incapable of focus detection or automatic focus adjustment is mounted by omitting the driving of the lens to an infinite-distance position when the lens is mounted. CONSTITUTION:When an interchangeable lens 1 is mounted on a camera body 2, a lens mounting detecting means 22 detects the mounting of the interchangeable lens 1. A lens driving means 21 operates under the control of a control means 23 in response to the detection output of the lens mounting to stop down the focus adjusting lens 11 for the interchangeable lens toward the infinite- distance position. When a decision means 24 decides that the interchangeable lens 1 is incapable of focus detection or automatic focus adjustment, an inhibiting means 25 inhibits the control operation of the control means 23 and the lens is not stopped down to the infinite-distance position. Consequently, even when the interchangeable lens 1 which is incapable of focus detection or automatic focus adjustment is mounted, the rational operation is performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an interchangeable lens camera.
It is particularly suitable for single-lens reflex cameras with automatic focus adjustment.

[Prior Art] Conventionally, an interchangeable lens single-lens reflex camera having an automatic focus adjustment function is generally provided with a lens position counter within the camera body to detect the amount of lens extension. This lens position counter is reset when the focusing lens of the interchangeable lens is retracted to the infinite position, and when the focusing lens is extended, it is counted up according to the amount of extension.
When it is renormalized, it is counted down according to the amount of renormalization. When attaching an interchangeable lens, it is necessary to retract the focusing lens of the interchangeable lens to the infinity position in order to reset the lens position counter.

[Problems to be Solved by the Invention] When attempting to expand the range of interchangeable lenses in the above-mentioned single-lens reflex camera with an automatic focus adjustment function,
In addition to regular refractive lenses, there is a demand for adding reflective telephoto lenses. Furthermore, in order to obtain special imaging effects such as perspective correction, it becomes necessary to add a shift lens that can be tilted. Furthermore,
In order to enable super-telephoto shooting, there is a need to provide super-telephoto lenses that achieve an ultra-long focal length at the expense of the F number, as well as high-magnification teleconverters that further lengthen the focal length of existing telephoto lenses. will also occur.

However, if the camera body is equipped with a focus detection device using the TTL phase difference detection method, it is often impossible to detect the focus with these lenses.For example, with a reflective telephoto lens, the focus detection device determined by the design of the camera body Focus detection cannot be performed unless the light flux passes between the inner and outer exit pupils of the reflective telephoto lens, and with a shift lens, accurate focus detection cannot be performed when the optical axis is offset from the center of the screen. If the F number is larger than the specified value, the focus detection light beam will be glared by the aperture, making it impossible to accurately detect the focus.When such a lens is attached to the camera body, the focus adjustment lens of the interchangeable lens may If the lens is automatically retracted to the infinity position, the photographer may misunderstand that a focus detectable lens is attached.

On the other hand, lenses designed for manual focus adjustment are not equipped with a power transmission mechanism to drive the lens from the camera body, so automatic focus adjustment is not possible. Since only detection is possible, it may be used in such a way that it can be attached to the camera body and only performs focus determination. When such a lens is attached to a camera body and the retraction operation towards infinity position as described above starts, the lens drive mechanism of the camera body may spin idle as there is no power transmission mechanism on the lens side. A malfunction occurs in which the machine does not stop.

The present invention has been made in view of these points, and its purpose is to enable rational operation even when an interchangeable lens that is not capable of focus detection or automatic focus adjustment is attached. The objective is to provide a camera with interchangeable lenses.

[Means for Solving the Problems] In order to solve the above problems, in the interchangeable lens camera according to the present invention, as shown in FIG. 1, an interchangeable lens for photographing (1), A camera with an automatic focus adjustment function consisting of a camera body (2) to which an interchangeable lens (1) is attached, and the camera body (2) is equipped with an interchangeable lens (1).
lens driving means (21) for driving the focusing lens (11), lens attachment detection means (22) for detecting attachment of the interchangeable lens (1), and lens attachment detection means (22) for detecting attachment of the interchangeable lens (1).
control means (23) for controlling the lens driving means (21) so as to retract the focusing lens (11) toward the infinite position when attachment of the interchangeable lens (1) is detected by;
and determining means (24) for determining whether or not the interchangeable lens (1) is a lens whose focus cannot be detected; and the determining means (24) determines that the interchangeable lens (1) is a lens whose focus cannot be detected. It is characterized in that it sometimes comprises a prohibition means (25) for prohibiting the control operation of the control means (23).

However, FIG. 1 is an explanatory diagram showing the configuration of the present invention in functional blocks, and in the embodiments described later, the main part of the above configuration is realized by a microcomputer program.

Note that the determining means (24) may be a means for determining whether the interchangeable lens (1) is a lens that cannot be automatically focused.Furthermore, the interchangeable lens (1) may have data specific to the lens fixedly stored therein. Storage means (13) and camera body (
2) read signal S from. read signal input means (12) for inputting K; and storage means (12) for sequentially inputting the read signal Sc;
13) to the camera body (2), and if a lens attachment signal ICP is sent from the interchangeable lens (1) to the camera body (2), Lens attachment detection means (2
The detection operation according to 2) can be easily performed. Also,
The interchangeable lens (1) is a power transmission device for automatic focus adjustment.
(15), the signal AFE indicating that the interchangeable lens (1) is a focus detectable lens, the open aperture value AVo of the interchangeable lens (1), etc. from the interchangeable lens (1) to the camera. By sending it to the body (2), the discriminating means (24) can easily perform the discriminating operation.

[Effect] Hereinafter, the operation of the present invention will be explained with reference to FIG.

When you attach the interchangeable lens (1) to the camera body (2),
Lens attachment detection means (22) detects attachment of the interchangeable lens (1). In response to this lens attachment detection output, the lens driving means (21) is operated under the control of the control means (23), and the focusing lens (11) of the interchangeable lens (1) is rotated toward the infinity position. However, the means for determining (24)
When it is determined that the interchangeable lens (1) is a lens in which focus detection or automatic focus adjustment is not possible, the prohibition means (
25) prohibits the control operation of the control means (23),
Renormalization toward the infinite position is not performed.

[Embodiment] FIG. 2 is a block circuit diagram showing the circuit configuration of a camera as an embodiment of the present invention. However, illustrations of parts not directly related to the focus detection operation are omitted. (
μC) is a microcomputer that performs calculations and sequence control for focus adjustment. (LEC) is a lens circuit provided in the interchangeable lens, which transmits information specific to the interchangeable lens to the microcomputer (μC). (A.F.C.
) is a focus detection circuit that photoelectrically converts the subject light that has passed through the lens and outputs focus detection data.
μC). (DSP) is a display circuit that displays the focus of the lens and that the focus cannot be detected. (ILM) is an auxiliary light emitting device that irradiates the subject with auxiliary light for focus detection. (M) is a motor for driving the focusing lens of the interchangeable lens, and the lens drive circuit (
The lens drive circuit (LDC), which extends and retracts the lens under the control of the LDC, receives motor drive speed signals, motor drive direction signals, and motor stop control signals from a microcomputer (μC). Based on this input, the motor (M) is driven. (ENC) is an encoder that detects the amount of rotation of the motor (M), and according to the predetermined amount of rotation of the motor (M), the microcomputer (
output a pulse to μC).

Here, the microcomputer (μC) uses a lens position counter N to know the amount of lens extension from the infinity position, which is the most retracted state, as an absolute amount.
, is built-in. This lens position counter N is reset to NL=O by an internal command when the lens is retracted to the infinite position, and when the lens is extended, a pulse from the encoder (ENC) is output by an internal command. When the lens is renormalized, the encoder (E
It is counted down in response to the pulse from NC). When the lens is extended to the closest position, the value of the lens position counter N becomes N1-=N+*ax.

This maximum extension amount Nwax differs depending on the lens, and is read into the microcomputer (μC) from the lens circuit (LEC) as lens-specific information.

(BAT) is a power supply battery, and a microcomputer (
μC) and other circuits. Power battery (BA
A time constant circuit consisting of a series circuit of a resistor (R1) and a capacitor (C1) is connected to both ends of the resistor (T).
The connection point between R1) and the capacitor (C1) is connected to the power-on reset terminal (RES>) of the microcomputer (μC).When the power battery (BAT) is connected, the power supply terminal (Vcc) of the microcomputer (μC) A power supply voltage is applied between the ground terminal (GND) and the microcomputer (μC) becomes active.
Until the charging voltage of the capacitor (C1), that is, the voltage applied to the reset terminal (RES) of the microcomputer (μC) reaches a predetermined voltage, the microcomputer (
When the voltage of the capacitor (C1) exceeds a predetermined voltage, the microcomputer (μC) is reset and starts operating from step #1 (see FIG. 3), which will be described later.

(SR) is a reset switch, and this switch is OFF.
When N is pressed, the lens is reset to the initial position. (S
ω) is an infinity position detection switch, which is turned on when the lens is retracted to the infinity position. (SM) is a main switch, which is turned on when using the camera. (S
L) is the shooting preparation switch, and normally the release button (
(not shown) is turned on at the first stroke. (SAF)
is the AF mode switch, and this switch (SAF)
When the switch (SAF) is ON, the autofocus mode is selected to drive the lens to the in-focus position based on the focus detection result, and when the switch (SAF) is OFF, the autofocus mode is selected based on the focus detection result. Display only,
A manual focus mode in which lens drive is not performed is selected. (SMZ) is a macro zone switch,
In a zoom lens with a macro mechanism, when the zoom ring is set to the macro zone, the auto Since the focus mode is disabled, in order to notify the microcomputer (μC) of this, the lens circuit (LEC) sends a signal S indicating that it is a macro zone.
Output MZ to a microcomputer (μC).

Next, the focus adjustment operation of the camera will be explained with reference to a flowchart. First, when the battery is installed and a power-on reset is performed, the microcomputer (μC) executes the programs starting from #1 shown in FIG. first,
#1 resets all flags. However, only the lens not installed flag LENOF (described later) should be set to 1, #
In step 2, lens data is input from the lens circuit (LEC). From the lens circuit (LEC), the lens attachment signal ICP, macro zone signal SMZ, macro lens attachment signal LCPR of equal or greater magnification, and M thick line extension amount N are input. wax, open aperture value AVo, focal length information ZFZ, conversion coefficient, A
An F enable signal AFE, an AF coupler signal AFCP, etc. are input to a microcomputer (μC). Here, the focal length information ZFZ is the focal length f(m+*
) is logarithmically transformed information, and in this embodiment, it is assumed to be expressed by the following equation.

ZFZ=8X(21og2(f/6.25)+11+
++■ Also, the conversion coefficient is a coefficient for converting the defocus amount DF into the lens drive amount ΔN. The AF enable signal AFE is a signal indicating that the interchangeable lens is a focus detectable lens. The AP coupler signal AFCP is a signal indicating that the interchangeable lens is equipped with a power transmission device 1il (AF coupler) for automatic focusing.

In #3, the presence or absence of the lens attachment signal ICP is determined. If the lens is attached, the lens circuit (LEC) supplies the lens attachment signal ICP to the microcomputer (μC), but if the lens is not attached, the lens attachment signal ICP is not supplied, so the microcomputer (μC) determines whether the lens is attached by checking the presence or absence of this lens attachment signal ■CP. If there is no lens attachment signal at #3, it is determined that the lens is not attached, and at #8, the lens is not attached. Set the flag LENOF to 1 and proceed to #10 (Fig. 4). Also, if there is a lens attachment signal in #3, it is determined that the lens is attached, and #
4, it is determined whether the flag LENOF is 1. If LENOF=1 in #4, it is determined that the lens is attached from the state where the lens is not attached, and the lens not attached flag L is set in #5.
Set ENOF to 0 and proceed to #6, in #6 500 theory Se
After waiting for the time e to elapse, the ω renormalization subroutine (FIG. 10) is executed in #7. Then, in #10, it is determined whether the main switch (SM) is ON. #1
If the main switch (SM) is not ON at 0, the process returns to #2 and the presence or absence of the lens attachment signal is determined. Therefore, if the battery is installed and processing starts from #1,
When a lens is attached during the loop from #2 to #10, the subroutine (1) of renormalization is executed after waiting for 500 asec.

Here, to explain the reason for waiting for 500 m5ec, the photographer often holds the lens in his hand when attaching the battery or lens. If you start retracting the lens immediately after the
Lens retraction may stop midway, damage the lens or camera drive system, or the photographer may become surprised and drop the camera. To prevent this, 5
After waiting for a time of 00 m5ec, lens retraction is started when the photographer takes his hand off the lens.

Next, if the main switch (SM) is ON in #10, the lens initial position calculation subroutine (Fig. 9) is executed in #15, and the ω renormalization subroutine (first
After executing the lens initial position setting subroutine (FIG. 11) in #25, it is determined in #30 whether the main switch (SN) is OFF. If the main switch (SN) is OFF, the ω renormalization subroutine is executed in #35, and the process returns to #2 (FIG. 3). If the main switch (SM) is not OFF in #30, proceed to #45.

FIG. 9 is a flowchart showing the contents of a subroutine for calculating the lens initial position. When this subroutine is called, first, the lens circuit (L E C) is
Enter lens data from .

In #1005, the macro lens attachment signal LCP
Determine the presence or absence of R. If the macro lens of equal or larger magnification is attached in #1005, the defocus amount DFs for setting the lens initial position is set to DF fine/2 in #1040, and the process returns to the step in which the subframe was called. Here, DF- is the maximum defocus amount that covers the range from the closest position of the lens to the infinity 1. #10
If a macro lens of 100% magnification or higher is not installed in 05,
Defocus amount DFs is determined in #1010 to #1030. In #1010, it is determined whether the focal length information ZFZ is 40 or less, and if ZFZ≦40, in #1020
Then, return with DFs=O. ZFZ with #1010
If >40, use #1030 to set the lens initial value l N s
The defocus amount DFs corresponding to the focal length information ZF
Calculate based on Z and return.

Here, the meaning of the algorithm for determining the initial lens position shown in #1010 to #1030 will be explained.

In this algorithm, the defocus amount DFs (μ Using the above formula (2), the defocus amount DFs at the initial lens position Ns was calculated for the focal length f of 24 mm to 800 mm, and the photographing magnification β = DFs/f was calculated. The results are shown in Figure 14.As can be seen from Figure 14,
The above formula 0 has a focal pressure of 111f (35 mm), which is often used.
The defocus amount DFs at the initial lens position Ns is determined so that a commonly used imaging magnification β (1/80 to 1/40) can be obtained for a lens with a diameter of 300 mm). If the focal length is handled in millimeters within the camera body, then simply DFs=β×f×100
It would be fine to set it to 0 [μ action], but in reality, within the camera body, the focal length r is treated as information ZFZ logarithmically compressed using the above equation 0. In this case, 1/8
Defocus 1DFs is set as a linear function of focal length information ZFZ so that the condition 0≦β≦1/40 is satisfied.
(μ ring) is not easy to find, but the above formula 0 realizes it.Using the above formula 0, the imaging magnification β
When calculating (f), β(“)cc (in(f) −
&n(6, 25X 4 )1/f. dβ/df=
If the maximum value is determined from the condition of o, (1/β)=46 when f''68m+@.

Also, when f==3311II, (1/β)=80.
5. When f=300ms, (1/β)=81.7.

Moreover, in the above formula 0, the multiplication coefficient is 64 = 2', so after subtracting the constant 40 from the focal length information ZFZ, the defocus amount DFs at the initial lens position Ns can be calculated by simply shifting to the left six times. You can ask for it. Therefore, the defocus amount DFs of the lens initial value WNs is determined from the focal length information ZFZ read from the lens circuit (LEC).
can be easily calculated, the calculation time can be shortened, and the storage capacity of the calculation program can be reduced. Furthermore, compared to a method in which the defocus amount DFs of the lens initial position Ns is stored in advance according to various focal lengths f, the storage capacity of the ROM can be reduced.

(Left below) Table 1 However, in the table above, * indicates when a 28-135mm zoom lens is at 135mm, and ↑ indicates when a 70-2101 zoom lens is at 2101mm.
When the customer is in a 75-300mm zoom lens
This is the data when it is at 00mm.

Table 1 shows commonly used photographic magnification β and maximum defocus amount DF for lenses with various focal lengths.
+* is shown. In a wide-angle lens with a focal length f of less than 35-1, the maximum defocus amount DFm is small, and it is considered that focus can be detected no matter where the lens position is.

Therefore, it is considered that the lens should be stopped at an infinity position so as to obtain the commonly used photographic magnification of 1/■. Therefore, in this embodiment, f≦24 va (Z F Z≦
40), it is set as DFs-0. On the other hand, for lenses with commonly used focal lengths (35 to 300 am), commonly used imaging magnifications are distributed in the range of 1/40 to 1/60. The range of photographic magnifications in which focus detection is possible is thought to be slightly wider than this, and focus detection is possible if the initial stop position of the lens is determined so that a photographic magnification within the range of 1/40 to 1/80 is obtained. It is thought that the probability that this will occur will be high. Therefore, in this example, f>24 mm (ZF
In the case of Z>40), using the above formula 0, 1/80≦
The defocus amount DFs of the lens initial position Ns such that β≦1/40 is calculated.

FIG. 10 is a flowchart showing the contents of the ω renormalization subroutine. When this subroutine is called, a subroutine for lens condition determination is executed in #1100. Here, the lens condition determination subroutine is
An example will be explained in FIGS. (a) and (b).

In FIG. 12(a), first, in #2000, the presence or absence of the lens attachment signal ICP is determined. If there is a lens attachment signal in #2000, it is determined in #20LO whether the open aperture value AVo of the lens is smaller than a predetermined value AFAV. Here, the predetermined value AFAV is the size of the AF pupil through which the focus detection light beam passes, expressed as an aperture value. WI wide aperture value A V
If o is smaller than the predetermined value AFAV, the focus detection light beam passing through AF@ will not be eclipsed by the lens.

If AVo<AFAV in #2010, the presence or absence of the AF enable signal AFE is determined in #2020. #A in 2020
If the F enable signal AFE is present, it is determined that a focus detectable lens is attached, and the process returns with the lens condition plug LOKF set to 1 in #2030. If there is no lens attachment signal in #2000, lens renormalization cannot be performed, so the process returns with the lens condition flag LOKF set to O in #2040. If AVo≧AFAV in #2010, the focus detection light flux passing through the AF pupil is vignetted by the lens, so it is determined that accurate focus detection cannot be performed, and the lens condition flag LOKF is set to 0 and the process returns in #2040. do. If there is no AF enable signal AFE in #2020, it is determined that a lens whose focus cannot be detected, such as a reflective telephoto lens or a shift lens, is attached, and #
At 2040, the lens condition flag LOKF is set to 0 and the process returns.

FIG. 12(b) is another example of lens condition determination, #2
After determining the presence or absence of the ICP installation signal in step 000, if there is an ICP installation signal, the presence or absence of the AF coupler signal AFCP is determined in #2025.

If AF coupler signal AFCP is present in #2025, AF
It is determined that a lens equipped with a coupler, that is, a lens that can be driven for focusing by the camera body motor, is attached, and the lens condition flag is set to LO in #2030.
Return with KF set to 1.

If there is no AF coupler signal AFCP in #2025, A
It is determined that a lens without a P coupler is attached, and the process returns with the lens condition flag LOKF set to 0 in #2040.

If the lens conditions shown in FIG. 12(a) or (b) are satisfied, the lens condition flag LOKF becomes 1, and if the lens conditions are not satisfied, the lens condition flag LOKF becomes 0. Returning to the flow in Figure 10, #
In step 1102, the lens condition flag LOKF is determined. #
If 1102 is L OK F-〇, #1104~#
Skip step 1115 and return. #1
If LOKF=1 at 102, lens renormalization starts at $1104. After starting lens drive in #1104, the infinity position detection switch (S■) is turned OFF in #1105.
Determine whether it is N. Switch at #1105 (Sω)
If the switch (Sco) is not ON, repeat the determination operation in #1105 until the switch (Sco) is turned ON. If the lens is retracted to the infinity position in #1105 and the switch (SQO) is ON, the lens is closed in #1110. stop renormalization,
The lens position counter NL is reset at $1115, and the subroutine returns to the called step.

FIG. 11 is a flowchart showing the contents of the subroutine for setting the lens initial position. When this subroutine is called, the lens condition determination subroutine is executed in #1200, and the lens condition flag LOKF is determined in #1202. If LOKF=O in #1202, #12
Skip steps 04 to #1215 and return. If LOKF=1 in #1202, the defocus amount DFs for setting the lens initial position is multiplied by the conversion coefficient K in #1204 to obtain the lens drive amount ΔN from the infinity position.
=DFsXK is calculated, and lens extension is started in #1205. In #1210, it is determined whether the lens drive amount has reached ΔN. If the lens driving amount has not reached ΔN in #1210, #1 until the lens driving amount reaches ΔN
The determination operation of 210 is repeated, and when the lens drive amount reaches ΔN in #1210, the lens drive is stopped in #1215, and the process returns to the step where the subroutine was called.

Returning to the flow of FIG. 4, in #45, it is determined whether the AP mode switch (SAF) is ON.

#45rIf the AF mode switch (SAF) is not ON, set the flag MF indicating manual focus mode to 1 in #50, proceed to #80, and set A in #45.
If the F mode switch (SAP) is ON, it is determined in #55 whether the flag MP is 1. MF=1 in #55
If so, it means that the switch (SAF) has just been turned on, and in #60, set the flag MP to 0 and proceed to #65. In #65 to #75, the above-mentioned lens initial position calculation,
Execute the ω renormalization and lens initial position setting subroutines to set the lens initial position, and then #1
Proceed to #45. If MF = 1 in #55, it means that the switch (SAF) has been ON for some time, and #
Proceed to 80.

In #80, the presence or absence of the lens attachment signal ICP is determined.

If the lens is not attached at #80, the flag LENOF indicating that the lens is not attached is set to 1 at #100, and the process proceeds to #105.If the photographic lens is attached at #80, the flag is set at #90. Determine whether LENOF is 1. If LENOF=1 in #90, it means that the lens has just been attached, and the flag LENOF is set in #95.
Set F to O, wait until 500 + 5 seconds have passed in #96, set the lens initial position in #65 to #75, then proceed to #145, #90″C″LENOF
If =1 is not the case, it means that the lens has been attached before, and the process proceeds to #105.

At #105, the macro zone switch (SMZ) is turned on.
In other words, it is determined whether the zoom lens is in the macro zone. Macro zone switch (SM) with #105
Z) is not ON, that is, if it is in the macro zone,
In #110, the flag SMZOFF indicating that the macro zone switch (SMZ) is OFF is set to 1, and in #125
If the macro zone switch (SMZ) is ON in #105, it is determined whether the flag SMZOFF is 1 in #115. If SMZOFF=1 at $115, it means that the macro zone switch (SR2) has just been turned on, and the flag SMZOFF! is set at #120. ” to 0
After setting the lens initial position in #65 to #75, proceed to #145, and sMZ in #115.

If FF is not 1, the macro zone switch (
SMZ) was turned on, and #125
Proceed to.

In #125, it is determined whether the reset switch (SR) is ON. If the reset switch (SR) is not ON at $125, turn it on at #130.
Set the flag 5ROFF, which indicates that the is OFF', to 1, and proceed to #145.
) is ON, it is determined in #135 whether the flag 5ROFF is 1.

If 5ROFF=1 in #135, it means that the reset switch (SR) has just been turned on, and #140
After setting the flag 5ROFF to 0 and setting the lens initial position in #65 to #75, proceed to #145, #135
If 5ROFF' = 1, it means that the reset switch (SR) has been turned on before, and the lens has already been set to the initial position, so #65 to #
The process proceeds to #145 without performing the lens initial position setting in step 75.

Therefore, after setting the lens initial position (#15 to #25) immediately after turning on the main switch (SM),
Immediately after the P mode switch (SAF) is turned on, immediately after the lens is attached, or when the macro zone switch (S to Z
) is turned on, or the reset switch (SR
) is turned ON, or when the focus cannot be detected even after performing the low contrast scan described below (#25).
The lens initial position is set only in cases (see 2); in other cases, the lens initial position is not set. Therefore, when shooting similar scenes or when shooting multiple pictures in succession When the probability of focusing near the previous lens position is high, as in the case of the previous lens position, the initial lens position is not set, and power consumption is lower than when the lens initial position is set every time the focus is detected. , and the time required for focus adjustment is shortened.

In #145, it is determined whether the photographing preparation switch (Sl) is ON. If the photographing preparation switch (Sl) is not turned on, the entire display is turned off in #40 and the process returns to #30. Below, #30, #45, #80, #105, #125
, and #145, check the status of the main switch (SM), AP mode switch (SAF), lens attachment signal ICP, macro zone switch (SM2), reset switch (SR), and shooting preparation switch (Sl). Monitor.

In the middle of this loop, the main switch (SN) is turned off.
When it is, as mentioned above, ω renormalization (#35)
and go through the loop #2 to #10 again until the lens is attached or the main switch (SN) is turned off.
Wait until N. Also, in the middle of the loop from #30 to #145, switches (sAF), (SMZ), (SR
) is turned on, or when a lens is attached, the lens initial position set (#65~
#75) In this way, the camera is waiting for the shooting preparation switch (Sl) to be turned on, but #14
If the photographing preparation switch (Sl) is turned ON in step 5, the process proceeds to #175 (FIG. 5) to start focus detection.

Focus detection is performed in #175, and it is determined in #180 whether focus detection is impossible. If focus cannot be detected in #180, proceed to #290 (Figure 7) to perform focus determination.
If the focus cannot be detected in #180, it is determined in #185 whether the brightness is low. If the brightness is low in #185, proceed to #330 (Fig. 8) to emit the auxiliary light. If the brightness is not low in #185, proceed to #190 (Fig. 8) to find a lens position where contrast can be obtained. Proceeding to Fig. 6), a low-contrast scan is performed, but by limiting the range of the low-contrast scan to the narrowest possible range, an effort is made to shorten the time required for the low-contrast scan. In other words, in the focus detection device, the range in which focus detection is possible is determined, and from the current lens position to the rear focus side +DFa,
Assuming that focus detection is possible within the defocus amount range of -DFa on the front bin side, focus detection is possible within the range of ±DFa from the current lens position without changing the lens position. It is within. Therefore, #190
(Fig. 6), the scanning amount in the feeding direction is ΔN=N
Calculate as max-NL-DFaXK. This allows the DF to be extended even if it is not extended to the maximum extension position N wax.
If the edge is extended to the front position by aXK, the maximum extension position Nwax will also be within the focus detectable range 2DFa.Next, in order to know the scan direction, use #200
It is determined whether the flag FOWF is 1 or not. This flag FOWF is a flag indicating that scanning is to be performed in the direction (FOWard). When performing a low-contrast scan for the first time, the flag FOWF has been reset, so FOWF is not 1, so initially #
Proceed to 205, #205 as FOWF-1, #22
Proceed to 0. In #220, a signal is output to the lens drive circuit (LDC) to drive the lens (in the feeding direction), and #
After focus detection is performed in step 225, it is determined in step #230 whether focus detection is impossible. If the focus cannot be detected in #230, the flag FOWF is reset in #233, and the process proceeds to #290 (Fig. 7) to determine focus. If the focus cannot be detected in #230, the lens is adjusted in #235. It is determined whether the drive amount has reached ΔN. If the lens driving amount has not reached ΔN in #235, the process returns to #225, and while continuing to drive the lens in the extending direction, it is determined whether focus cannot be detected. If the lens drive amount has reached ΔN in #235, the lens drive is stopped in #240, and the flag F is set in #245.
Determine whether OWF is 1. FOWF = $245
If it is 1, this means that a lens position where the focus can be detected was not found even though scanning was performed in the extending direction, and the process returns to #200 to perform scanning in the extending direction. If FOWF=1 in #200, it means that the scanning in the feeding direction has already been completed, so in #210, the scanning amount in the feeding direction is set to ΔN.
=Nmax. This is to reset the counter by carrying it out to the end. In #215, the flag FOWF is set to indicate that the scan is in the renormalization direction.
Set to 0 and proceed to #220. At $220, the lens drive (
A signal is output to the lens drive circuit (LDC) in order to perform
5. This time, since FOWF=1, #20
It does not return to 0 and proceeds to #250, that is, #24
If FOWF is not 1 in 5, it means that both the scanning in the extending direction and the scanning in the retracting direction were performed, but no lens position where focus detection was possible was found, so in preparation for the next focus detection, # After executing the lens initial position calculation subroutine in 250 and executing the lens initial position setting subroutine in #252, the subroutine is executed in #255.
(FIG. 7) indicates that the focus cannot be detected. If focus detection becomes possible in #230 during scanning in the retraction direction, the flag FOWF is reset in #233, and the process proceeds to #290 (FIG. 7) to perform focus determination.

When displaying focus detection failure in #255 (Fig. 7), #2
At 60, set the low contrast scan end flag LSENDF to 1
shall be. This flag is a flag to indicate that a lens position where the focus can be detected was not found even though low contrast scanning was performed.Next, after returning the flag FOWF indicating the scan direction to 0 in #265, # At step 270, it is determined whether the photographing preparation switch (Sl) is ON. #27
If the shooting preparation switch (Sl) is not ON at 0, #4
Clear all display with 0 and return to #30. If the photographing preparation switch (Sl) is ON in #270, focus detection is performed in #275, and it is determined in #280 whether focus cannot be detected. If the focus cannot be detected in #280, the process returns to #270.

If the focus is not detected in #280, the low contrast scan end flag LSENDF is set to O in #290, and #29
5 to determine whether the image is in focus. If it is determined that the focus is not in focus in #295, the process proceeds to #300 to erase the in-focus and focus detection failure display, and in #305, the lens drive amount ΔN=DFXK is calculated based on the defocus 1LDF, and in #310
to start driving the lens. In #311, it is determined whether the lens drive amount has reached ΔN. If the lens drive amount has not reached ΔN in #311, the determination operation in #311 is repeated until the lens drive amount reaches ΔN. If the lens drive amount reaches ΔN in #311, the lens drive is stopped in #312. , return to #270. If the shooting preparation switch (SL) remains ON in #270, focus detection is performed in #275, and focus determination is performed again in #295 after going through #280 to #290, as described in #305 above. Since the lens is driven toward the in-focus position in steps #310 and 310, there is a high possibility that in-focus will be achieved here.

If it is in focus at #295, the focus is displayed at #315,
In #320, it is determined whether the photographing preparation switch (Sl) is ON. #320 prepares for shooting in Sochi (Sl)
If N, the determination operation of #320 is repeated until the photographing preparation switch (Sl) is no longer ON, resulting in a so-called focus lock state. Although unrelated to the present invention, in a camera in focus priority mode, release is permitted in this focus lock state, and when the release button (not shown) is pushed to the second stroke, the camera is released. It performs a release operation. If the shooting preparation switch (Sl) is no longer ON in #320, #40
Turn off the display and return to #30. That is, by turning off the photographing preparation switch (Sl), the above-mentioned focus lock state is released.

Next, when passing through #330 in Figure 8, it is determined that the brightness is low and focus cannot be detected in #185 and #180 (Figure 5), so auxiliary light emission is necessary. However, there are cases where it is useless to emit the auxiliary light, so #3
The determination is made in steps 30 and #335. Here, the auxiliary light emitting device (ILM) shown in FIG. The focus detection circuit (AFC) includes a light emitting diode provided and an optical system for projecting light.
It includes a focus detection optical system using the TL phase difference detection method, and its optical axis coincides with the optical axis of the photographic lens. Therefore, the luminous flux range of the optical system for auxiliary light projection and the luminous flux range for focus detection have a disparity, and from a predetermined distance in front of the photographic lens (varies depending on the angle of view), the luminous flux range for focus detection The luminous flux range of is completely included in the luminous flux range of the optical system for auxiliary light projection.This distance is the lower limit of the range in which the auxiliary light can illuminate the subject to enable focus detection, and it is closer than this. It is useless to emit auxiliary light on the subject.

Further, when a long focal length lens is attached to the camera, the auxiliary light is vignetted by the lens barrel, so the auxiliary light does not hit the subject, and even if the auxiliary light is emitted, it may be wasted. Note that the lower limit of the range in which the subject can be illuminated to enable focus detection with fill light can be reduced by adopting a TTL fill light system, but the upper limit of the range in which focus detection is possible with fill light irradiation can be made smaller. The thing is, the reach distance of the auxiliary light is about 101m at most, so we can't expect much from it, so with #330, the focal length of the lens is f.
is 250 am or more, and in #330 f≧2
If it is 50, it is determined that the auxiliary light may be blurry due to the long lens length or large lens diameter, so proceed to #190 (Figure 6) without emitting the auxiliary light, and set the low control light. Perform a scan.

In addition, when shooting with a long focal length lens, there are many long-distance shots where the auxiliary light does not reach, so there is not much problem with disabling the auxiliary light.
At step 35, it is determined whether there is a macro lens attachment signal LCPR of equal or greater magnification. If a macro lens of equal or larger magnification is attached in #335, it is determined that the shooting is at close range, which is closer than the lower limit of the range where focus detection is possible with auxiliary light irradiation, and the auxiliary light is not emitted. Proceed to #190 (Fig. 6) and perform a low-contrast scan.If a macro lens of 100% magnification or higher is not attached in #335, emit an auxiliary light in #340, perform focus detection in #345, and # At 350, it is determined whether focus detection is impossible. The auxiliary light is emitted only for a predetermined period of time for each focus detection.

If the focus is not detected in #350, proceed to #395.
If focus cannot be detected in #350, perform ω renormalization in #355 to reset the counter, and #
At 370, auxiliary light is emitted, at #375 focus detection is performed, and at #380 it is determined whether focus detection is impossible. #38
If the focus is not detected at 0, proceed to #395, $38
If the focus cannot be detected with 0, it is determined whether the lens is at the initial position in #381, and if the lens is not in the initial position, the lens initial position is set in #382, and #3
In step 83, a flag indicating that the lens is at the initial position is set, and if focus detection is not possible even in the 0th focus detection, the process proceeds to #390, and the process proceeds from #381 to #385 to display a focus detection failure display. Press #390 to turn on the shooting preparation switch (Sl)
) is ON. If the photographing preparation switch (Sl) is ON in #390, the process returns to #375. #39
If the shooting preparation switch (Sl) is not ON at 0, #4
Turn off the display with 0 and return to #30.

In #395, the focus detection failure display is erased, and in #400, it is determined whether focus is achieved. If the focus is #400, #4
20 indicates the focus, and #425 sets the shooting preparation switch (
SL) is ON. If the shooting preparation switch (Sl) is ON in #425, the shooting preparation switch
Repeat the determination in #425 until Sl) is no longer ON. If the photographing preparation switch (Sl) is no longer ON at step 25, the display is turned off at step #40, and the process returns to step #30. #400
If the lens is not in focus, lens drive IΔN=DFxK is calculated from the defocus amount DF in #405, and lens drive is started in #410. In #412, the lens drive amount is ΔN
Determine whether it has been reached. Lens drive amount is ΔN in #412
If the lens drive amount has not reached ΔN, the determination operation in #412 is repeated until the lens drive amount reaches ΔN. If the lens drive amount reaches ΔN in #412, the lens drive is stopped in #413.
In #415, it is determined whether the photographing preparation switch (Sl) is ON. At #415, the shooting preparation switch (Sl) is turned on.
If so, the process returns to #370, and if it is not ON, the display is turned off in #40 and the process returns to #30.

Determining the defocus amount DFs in the lens position calculation subroutine (Fig. 9) described above (#1010 to #10)
In the algorithm 30), focal length information ZF
Depending on Z, the defocus amount DF of the lens initial position Ns
s is being calculated.

FIG. 13 is a flowchart showing a modification of this algorithm, which can be used in place of steps #1010 to #1030. In #1500,
Determine whether the focal length f is 28m5 or less (ZFZ≦a>. If f≦28mm in #1500, select #151
At 0, set the shooting magnification β to 0 and proceed to #1570.
If f > 28mm in #1500, determine if the focal length is less than or equal to 210 wheels (Z F Z ≦ b) in #1520. If f > 28 mm in #1520, shoot in #1530. Set (1/40) as the magnification β and proceed to #1570, f>210+*m in #1520
If so, #1540 and focal length r of 600 am or less (
It is determined whether Z F Z ≦c). In #1540, “If ≦6001, set (1/60) as the imaging magnification β in #1550, and proceed to #1570, #1540
If f>600mm, set (1/100) as the imaging magnification β in #1560 and proceed to #1570, #1
At 570, the lens extension amount DFs from the infinity position to the lens position Nb is calculated by multiplying the imaging magnification β by the focal length information ZFZ. In the algorithm shown in FIG. 13, the focal length f is, for example, 35+*m to 105mm.
In this case, the defocus amount DFs is selected, which is the focal length f multiplied by the imaging magnification β=(1/40). In other words, the lens is always initially set at a position where an imaging magnification of (1/40) can be obtained.

[Effects of the Invention] As described above, the present invention provides an interchangeable lens camera with an automatic focus adjustment function, when a lens that cannot perform focus detection or automatic focus adjustment is attached, the lens cannot be driven toward an infinity position. Since this is omitted, there is an effect that rational operation can be performed even when these lenses are attached.

Therefore, by adding reflective telephoto lenses, shift lenses, ultra-long focal length lenses, high-magnification teleconverters, manual focusing lenses, etc. to the interchangeable lens group, it is possible to construct a complete system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention, FIG. 2 is a block circuit diagram of an embodiment of the present invention, and FIGS.
The figure is a flowchart showing the same operation as above, and FIG. 14 is an explanatory diagram of the same operation. (1) is an interchangeable lens, (2) is a camera body, (11)
is a focusing lens, (12) is a reading signal input means, (
13) is a storage means, (14) is a data sending means, (15)
) is a power transmission mechanism, (21) is a lens driving means, (22
) is the lens attachment detection means, (23) is the control means, (24
) is a discrimination means, and (25) is a prohibition means.

Claims (8)

[Claims] (1) A camera with an automatic focus adjustment function consisting of an interchangeable lens for photographing and a camera body to which the interchangeable lens is attached, the camera body having a lens drive means for driving the focus adjustment lens of the interchangeable lens; A lens attachment detection means for detecting attachment of an interchangeable lens; and a control means for controlling a lens driving means so as to retract a focusing lens toward an infinity position when attachment of an interchangeable lens is detected by the lens attachment detection means. a determining means for determining whether the interchangeable lens is a lens whose focus cannot be detected; and a prohibiting means for prohibiting a control operation of the control means when the determining means determines that the interchangeable lens is a lens whose focus cannot be detected. An interchangeable lens camera characterized by comprising: (2) An interchangeable lens has a storage means that fixedly stores data specific to the lens, a read signal input means that inputs a read signal from the camera body, and a read signal input means that sequentially inputs data from the storage means to the camera body based on the read signal. 2. The interchangeable lens camera according to claim 1, further comprising data sending means for sending data. (3) The data fixedly stored in the storage means includes focus detection capability data indicating whether focus detection is possible, and the determining means determines whether the interchangeable lens is unable to detect focus based on the focus detection capability data read from the interchangeable lens. 3. The interchangeable lens camera according to claim 2, further comprising means for determining whether the lens is a lens or not. (4) The interchangeable lens is a reflective telephoto lens, the storage means fixedly stores data specific to the reflective telephoto lens, and the determination means determines whether or not the interchangeable lens is a lens whose focus cannot be detected by determining the data. 3. The interchangeable lens camera according to claim 2, further comprising means for: (5) The interchangeable lens is a shift lens, the storage means fixedly stores data unique to the shift lens, and the discrimination means is means for discriminating that the interchangeable lens is a lens whose focus cannot be detected when the data is detected. 3. The interchangeable lens camera according to claim 2. (6) The data fixedly stored in the storage means includes data on the maximum aperture value, and the determination means determines that the interchangeable lens is a lens whose focus cannot be detected when the maximum aperture value is larger than a predetermined value. 3. The interchangeable lens camera according to claim 2, further comprising means for: (7) A camera with an automatic focus adjustment function consisting of an interchangeable lens for photographing and a camera body to which the interchangeable lens is attached, the camera body including a lens driving means for driving the focus adjustment lens of the interchangeable lens; A lens attachment detection means for detecting attachment of an interchangeable lens; and a control means for controlling a lens driving means so as to retract a focusing lens toward an infinity position when attachment of an interchangeable lens is detected by the lens attachment detection means. a determination means for determining whether the interchangeable lens is a lens that cannot be automatically focused; and a prohibition that prohibits a control operation of the control means when the determining means determines that the interchangeable lens is a lens that cannot be automatically focused. An interchangeable lens camera characterized by comprising: means. (8) The interchangeable lens is a lens that does not have a power transmission mechanism from the lens driving means of the camera body to the focusing lens, and when the determining means detects that the interchangeable lens is a lens that does not have the power transmission mechanism. 8. The interchangeable lens camera according to claim 7, further comprising means for determining that the interchangeable lens is a lens that cannot be automatically focused.