JPH02240642A - Camera lens system - Google Patents

Abstract

PURPOSE:To shorten the time until shutter releasing by controlling so that a lens moving range is narrowed as the depth of an object becomes greater. CONSTITUTION:When the photometric range finding switch 21 of a camera main body 1 is turned on, the light quantity detected by a photometric light receiving element 6 is transmitted to a photometric arithmetic circuit 7, and exposure quantity is stored. Simultaneously a range finding sensor 16 operates by the instruction of a microcomputer 10, and a range finding arithmetic circuit 17 determines the lens feeding amount, and serially communicates with a microcomputer 55. An instruction about the rotating direction of a driving motor 53 is given to a lens driving circuit 54 to move a photographing optical system G1. Since a lens moving amount can be detected through the use of a ratchet 60 and a counter 57, the photographing optical system G1 is moved by the moving amount instructed by the side of the camera main body 1, and is stopped at a focal point. Consequently, the lens moving range can be narrowed as the depth of an object becomes greater, and the time until the releasing of the shutter can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to an autofocusable camera/lens system, and in particular, to a first lens position corresponding to a set first focusing position and a second focusing position. A camera/lens system comprising: storage means for storing second lens positions corresponding to respective positions; and lens movement means for moving the lens only within the range of the first and second lens positions during a search operation. It is about improvement.

In addition, the search operation referred to in the present invention refers to, for example, when the distance measurement cannot be performed accurately for objects with low contrast or low brightness, etc., the lens is moved back and forth in the range from ω to the closest distance to get closer to the focus. It even has a state (means an action that has been performed conventionally).

(Background of the Invention) In this type of system that is capable of autofocus (hereinafter referred to as AP), it is desirable that the focusing range is as wide as possible (for example (1) to 0.5 m). etc., when the shooting range is between 5m and 1m, the lens will be driven for areas other than 5m = 1m, so
It has the drawbacks of wasting time and missing photo opportunities. In view of this, the present applicant has proposed a system in which electrical (or mechanical) restrictions are added to prevent the lens from moving below, for example, 5 m to 1 m. but,
Even with these restrictions, the AF speed is finite, and although it is considerably reduced compared to conventional cameras, there is still the risk of missing a photo opportunity (more on this later).
.

(Object of the Invention) An object of the present invention is to provide a camera/lens system that can solve the above-mentioned problems and reduce the chance of missing a photo opportunity when taking a photograph that requires a search operation. It is.

(Features of the Invention) In order to achieve the above object, the present invention sets the drive range of the lens by the lens moving means to the first and second ranges stored in the storage means, depending on the aperture value and the focal length of the lens at that time. A lens drive range control means is provided, which narrows the range of movement of the lens to be narrower than the range of 2. According to the aperture value and focal length of the lens at that time, that is, as the depth of field becomes deeper, the range of movement of the lens is narrowed, and the shutter speed is reduced. It is characterized by shortening the time until release.

(Embodiments of the Invention) Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, 1 is a camera body, and 50 is the camera body 1.
This is an interchangeable lens body detachably attached to the camera mount 1a and the lens mount 51a. 3 is a mirror, 4 is a pentaprism, 5
6 is an eyepiece lens, and 6 is a light receiving element for photometry. Reference numeral 7 denotes a photometric calculation circuit, which is connected to a film sensitivity information input circuit 8, a shutter control circuit 9, and a microcomputer 10.

34 is a focal brain shutter, 3a is a mirror rotating shaft, and 3b is an operating bin, which faces the mirror drive cam 11. Reference numeral 12 denotes a mirror drive motor, which is connected to a motor drive circuit 13. Reference numeral 14 denotes a film winding and rewinding motor, which is connected to a motor drive circuit 15.

A distance measuring sensor 16 is connected to a distance measuring calculation circuit 17. 18 is the battery that operates the entire camera system, 1
9 is a main power switch, and 20 is a DC/DC converter, which is connected from the battery 18 to the microcomputer 10. 21 is a photometering and distance measuring switch, and 22 is a release switch. For boat fishing, use switch 21.2.
Reference numeral 2 denotes a two-stage stroke switch, which is configured such that the first stroke of the release button turns on the switch 21, and the second stroke turns on the switch 22.

Reference numerals 23a to 23e are a group of contact point bins on the side of the camera body 1, which are arranged near the mount 1a. Reference numerals 52a to 52e are contact bin groups on the side of the interchangeable lens body 50, which are opposed to the contact bin groups 23a to 23e on the camera side.

Gl and G2 are optical lenses for photographing. 53 is a lens drive motor used for focus adjustment, and a lens drive circuit 54
is connected to. As the lens drive motor 53 rotates, the number of pulses is input to the counter 57 via the ratchet 60. Note that the counter 57 is set to be incremented when the lens G1 moves in the {circle around (2)} direction. Reference numeral 61 denotes an aperture drive circuit, which is connected to the microcomputer 55 and to a known pulse motor 56, by which the aperture is driven. 63 is a far point side limit switch that sets a far point side limit, and 64 is a close side limit switch that sets a close side limit.

Next, the operation of the camera system having the above configuration will be explained.

First, by turning on the main power switch 19 of the camera body 1 and exciting the DC7DC converter 20, the converter 20 supplies an operable constant voltage to the microcomputer IO. Next, switch 2 for photometry and distance measurement.
When 1 is pressed down, the amount of light detected by the photometric light receiving element 6 is transmitted to the photometric calculation circuit 7, and the exposure amount is stored using a known method. Further, since the photometering and distance measurement switch 21 also serves as a trigger switch for automatic distance measurement, when the photometer and distance measurement switch 21 is pressed down, the microcomputer 1
The distance measurement sensor 16 is activated in response to the instruction, the distance measurement calculation circuit 17 performs distance measurement calculation using a known method, the amount of lens extension is determined, and a known serial communication is carried out with the microcomputer 55 on the side of the interchangeable lens body 50. is performed, and the direction of rotation of the drive motor 53 is instructed to the lens drive circuit 54, so that the photographing optical system Gl is moved. At this time, the contents of the counter 57 are changed by the ratchet 60 in response to the movement of the lens, and the amount of movement of the lens can be detected by the microcomputer 55 reading the number of pulses. The imaging optical system Gl is moved according to the instructed movement amount, and the projection optical system Gl is stopped at the in-focus position. - When fishing on a boat, distance measurement is performed again, and when it is determined that the camera is in focus, a focus display is performed on the camera body 1 side, and a focus sound is generated. The detailed operation of the camera thereafter is omitted since it is not directly related to the present invention. However, since the operation of AF is important, although it is well known, it will be briefly explained.

As mentioned above, the photographing range is 5 m to 1 m indoors.

In particular, the distance measuring device of an eye reflex camera requires lens replacement, operation, etc.
Due to the distance, etc., a TTL focus detection device using a passive light receiving element such as a CCD line sensor is often used, and is suitable for measuring horizontal patterns, low contrast objects, low brightness objects, etc. In such cases, the rangefinder will not work accurately unless it is very close to focus. Therefore, in such a case, as a search operation (to bring it to a state where it is quite close to being in focus), as is well known, (1) ~
Performs a back-and-forth motion up to a nearby point.

At this time, even though the subject is within 5m to 1m, c
The object will move from 0 to 065 m, and there is a risk of missing a photo opportunity. Therefore, as mentioned above, for example, 5m
The applicant has proposed a lens in which electrical (or mechanical) restrictions are applied so that the lens does not move below 1 m. However, it goes without saying that it still takes some time to move.

Therefore, in this embodiment, in order to shorten the moving time, the depth of field is taken into account, the moving range is narrowed, and the camera is made more resistant to photo opportunities.This will be explained below using a flowchart. Although there are some parts that overlap with the above description of the operation, it will be explained as a series of operations.

As mentioned above, turn on the main power switch 19 on the L side of the camera body (hereinafter simply referred to as the camera side) and turn on the D C/D
By energizing the C converter 2o, the converter 2o supplies a constant operational voltage to the microcomputer IO. At the same time, contact bin 23c1 contact bin 5
An operable constant voltage is also supplied to the microcomputer 55 on the side of the interchangeable lens body 50 (hereinafter simply referred to as the lens side) through 2c. As a result, the operation from step 1 in FIG. 2 is started.

[Step 1.2] When voltage is supplied to the microcomputer 55, the microcomputer 55 clears the far point side and near point side limiter flags as an initialization process.

On the other hand, when the photometric and distance measuring switch 21 is pressed next, the amount of light detected by the photometric light receiving element 6 is transmitted to the photometric calculation circuit 7, and the exposure amount is stored in a known manner. Furthermore, since the photometering and distance measurement switch 21 also serves as a trigger switch for automatic distance measurement, when the photometer and distance measurement switch 21 is pressed down, the distance measurement sensor 16 is activated according to instructions from the camera side microcomputer 10. , distance measurement calculation circuit 1 using a known method.
A distance measurement calculation is performed in step 7, and if distance measurement is possible, the amount of lens extension is determined, and known serial communication is performed with the microcomputer 55 on the lens side.

At this time, if distance measurement is not possible because the contrast of the subject is low or the amount of defocus is too large, the microcomputer IO on the camera side sends a command to drive the lens in the closest direction to the microcomputer on the lens side. 55.

While photometric distance measurement is being performed on the camera side, steps 3 to 7 are executed on the lens side.

[Step 3.4] Far point side limiter setting switch 63
If it is in the ON state, read the counter 57, store the counter value as the far point side limiter point, and set the far point side limiter setting flag.

[Step 5.6] Close side limiter setting switch 64
If it is ON, read the counter 57 and store the counter value as the nearest limiter point.
Set the closest limiter setting flag.

[Step 7] If no drive command has been received from the camera side, return to step 3.

It goes without saying that the far point side limiter point and the close side limiter point will not fulfill their original role unless they are set at different subject distances. Further, since these memory functions are not related to the automatic focusing operation, the focus may be adjusted and set manually.

Next, when a drive command is received from the camera side, step 8
Proceed to step 6 [Step 8] As described above, if distance measurement is not possible on the camera side, a close direction search command is given to the lens, so proceed to step 9. Note that the closest direction search command is an instruction to drive in the closest direction until it hits the maximum amount.

[Step 9] A nearby direction search command is given.
First, the closest limiter setting flag is read, and if it is not set, the process branches to step 13.

[Step 10] If the close limiter has been set, a close limiter position calculation routine to be described later is called, and the close limiter position is corrected using the aperture value communicated from the camera side.

[Step 11] If the vehicle is already in the close limiter area, the process branches to step 12; otherwise, the process branches to step 13.

[Step 12] If the vehicle is already in the close limiter area, a collision flag is set, the collision is communicated to the camera side, and the drive is terminated.

[Step 13] If the camera is not in the close range limiter area, start driving the lens drive motor 53 in the close range direction, set a flag indicating that the motor is being driven, and notify the camera that the motor is being driven.

[Step 14] Read the closest limiter setting flag. If it is not set, the process branches to step 18.

[Step 15] If the close limiter has been set, a limiter position calculation routine is called and the close limiter position is corrected using the aperture value communicated from the camera side. The reason why the limiter position calculation routine is called in step 15 is to take into consideration the case where the subject brightness changes while the motor is being driven.

[Step 16] Compare the count value of the counter 57 and the close limiter correction value, and if it is already in the close limiter area, proceed to step 17; otherwise, proceed to step 18
branch to.

[Step 17] If the vehicle is already in the close limiter area, a collision flag is set, the collision is communicated to the camera, and driving is terminated.

[Step 18] If it is not in the closest limiter area, or if the closest limiter is not set, check the closest end collision, and if it is the closest end collision, branch to step 17 and set the collision flag. , the end is communicated to the camera side and the drive ends. If the closest end has not been reached, the process branches to step 19.

Note that the closest end collision is determined by a fixed time counter 56.
The determination is made based on whether the count value of is likely to change.

[Step 19] If the closest end has not been reached, determine the remaining drive amount, and if the remaining drive amount is greater than "0", return to step 14; if the remaining drive amount is less than "0", step 20 branch to.

Note that the remaining drive amount is determined by adding the drive amount to the count value of the counter 56 at the time of receiving the drive command from the camera-side microcomputer 10 to obtain the drive target position, and then calculating the drive target position and the current value of the counter 56. Find it from the difference.

[Step 20] When the remaining drive amount reaches "0", the lens drive motor 53 is de-energized, the motor drive flag is cleared, and the camera side is notified that the motor drive has ended, and the drive is ended. do.

To summarize the above description of the close direction drive, in the case of a search operation, step 16 or step 18 to restep 17
The camera side microcomputer 10 is notified that the drive has ended in the "lens abutting state", and the drive is ended.

If the in-focus position cannot be detected by driving the lens to the close end (or close limiter), the camera-side microcomputer 10 communicates an "infinite direction search command" to drive the lens in an infinite direction to the lens-side microcomputer 55. do.

[Step 211 When an infinite direction search command is given, the far point side limiter setting flag is first read out, and if it is not set, the process branches to step 25.

[Step 22] If the far point side limiter has been set, a far point limiter position calculation routine to be described later is called, and the far point side limiter position is corrected using the aperture value communicated from the camera side.

[Step 23] If the process is already in the far point side limiter area, the process branches to step 24; otherwise, the process branches to step 25.

[Step 24] If the vehicle is already in the far point side limiter region, the abutment flag is set, the abutment is communicated to the camera, and the drive is terminated.

[Step 25] If the lens is not in the far point side limiter region, start driving the lens drive motor 53 in the infinity direction, set a flag indicating that the motor is being driven, and notify the camera that the motor is being driven.

[Step 26] Read the far point side limiter setting flag, and if it is not set, branch to step 30.

[Step 27] If the far point side limiter has been set, a limiter position calculation routine is called and the far point side limiter position is corrected using the aperture value communicated from the camera. Note that the reason why the limiter position calculation routine is called also in step 27 is to take into consideration the case where the subject brightness changes while the motor is being driven.

[Step 28] Compare the count value of the counter 57 and the far point side limiter correction value, and if it is already in the far point limiter region, proceed to step 29, otherwise proceed to step 30
branch to.

[Step 29] If the vehicle is already in the far point side limiter region, the abutment flag is set, the abutment is communicated to the camera, and the drive is ended.

[Step 30] If it is not in the far point side limiter area or if the far point side limiter is not set, check the infinite end end, and if it is the infinite end end, branch to step 29 and set the end end flag. Then, the end is communicated to the camera and the drive ends. If the infinite end has not been reached, the process branches to step 31.

It should be noted that the determination of the collision with the infinite end is also made based on the fact that the count value of the counter 56 does not change for a certain period of time.

[Step 31] If the infinite end has not been reached, the remaining drive amount is determined, and if the remaining drive amount is greater than "0", the process returns to step 26, and if the remaining drive amount is below rOJ, the process branches to step 20.

Note that in determining the remaining drive amount in this case as well, the drive amount is added to the count value of the counter 56 at the time of receiving the drive command from the camera-side microcomputer 10, the drive target position is determined, and the drive target position and the count value of the counter 56 are calculated. Calculated from the difference between the current values.

To summarize the above explanation of infinite direction drive, in the case of search operation, step 28 or step 30 to step 29
The camera side microcomputer IO is notified that the drive has ended in the "lens abutting state", and the drive is ended.

If the in-focus position cannot be detected by driving to the infinity end (or far-point side limiter), the camera-side microcomputer 10 displays that focusing is not possible and ends the automatic focusing operation.

Above, we have explained the search operation in the near and infinite directions when distance measurement is not possible, but the operation is exactly the same when driving the lens by a specified amount from the camera, and the limiter on the far point side and the near side is set. For example, driving is terminated at the limiter point and movement of the lens outside the limiter is prohibited.

Next, the close limiter position calculation routine and the infinite limiter position calculation routine will be explained with reference to the flowcharts of FIGS. 3 and 4.

- Proximity Limiter Position Calculation Routine (Figure 3) [Step 50] If communication of the aperture value is received from the camera side, the process branches to Step 52. If not received, step 5
Branch to 1.

[Step 51] Set the aperture value to the open value of the lens.

[Step 52] Set the limiter correction value by the aperture (=aperture value×minimum circle of confusion×2÷distance ring extension amount per pitch of ratchet 6o).

[Step 53] Set the closest limiter correction value (=limiter correction value based on the closest limiter setting value ten apertures).

- Far Point Limiter Position Calculation Routine (Fig. 4) [Step 60] If communication of the aperture value has been received from the camera side, the process branches to Step 62. If it has not been received, the process branches to step 61.

[Step 61] Set the aperture value to the open value of the lens.

[Step 62] Set the limiter correction value by the aperture (=aperture value×minimum circle of confusion×2÷distance ring extension per one pitch of the ratchet 60 [1).

[Step 63 Set the far point side limiter correction value (=far point side limiter correction value - limiter correction value by aperture).

According to this embodiment, the distance limit range of two arbitrarily set points is narrowed according to the aperture value and the focal length of the lens (in this embodiment, the focal length is assumed to be fixed). - You can focus quickly and there is almost no risk of missing a photo opportunity.

More specifically, by further reducing the range in consideration of the depth of field, the time required for shirt release is attempted to be shortened. In other words, the range is reduced by the aperture value of the AE on the camera side and the focal length of the lens.

Below, to explain with an example, the focal length of the lens is 50
mm, and the circle of least confusion is 35 μm, the range in focus from tm to 5 m for each photographic aperture is as shown in Table 1.

Table 1 As shown in this example, when shooting at F22, for example, even if the lens movement range is not limited to 5m to 1m, in other words, even if the movement range is limited to 2.05m-1.34m, It can be seen that the range of 5m to 1m produces a photograph with the correct bint.

Naturally, since the movement range is narrowed, the time required to release the shirt is shortened, and there is almost no chance of missing a photo opportunity.

(Modification) In this embodiment, a limiter switch on the far point side and a limiter switch on the near side are provided.
The far point and near point (close) limiter positions may be sequentially set using two switches.

In addition, the far point and close limiter setting values are transmitted to the camera-lens data communication lines 52a to 52c and 23a to 23.
c, the information may be communicated to the camera side, stored in the camera side microcomputer 10, and the driving range may be limited on the camera side. Furthermore, a far point side limit switch 63 and a close side limit switch 64 are provided on the camera body 1,
The setting storage of the driving range and the restriction of the driving range may all be performed on the camera side.

(Effects of the Invention) As described above, according to the present invention, the driving range of the lens by the lens moving means can be adjusted according to the aperture value and the focal length of the lens at that time. A lens drive range control means is provided, which narrows the range of movement of the lens to be narrower than the range of 2. According to the aperture value and focal length of the lens at that time, that is, as the depth of field becomes deeper, the range of movement of the lens is narrowed, and the shutter speed is reduced. Since the time required to release the camera is shortened, it is possible to reduce the chance of missing a photo opportunity when taking a picture that requires a search operation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 to 4 are flow charts showing its operation. l...Camera body side, 10...Microcomputer, 50...Interchangeable lens side, 53
... Lens drive motor, 54 ... Lens drive circuit, 55 ... Microcomputer, 57 ... Counter, 60 ... Ratchet, 63...Far point side limit switch, 64
・・・・・・Nearest limit switch, GIG2...
...Optical lens for photography.

Claims (1)

[Claims] (1) A storage means for storing a first lens position corresponding to a first focal position to be set and a second lens position corresponding to a second focal position to be set; and a lens moving means for moving the lens only within the range of the second lens position, the driving range of the lens by the lens moving means is determined according to the aperture value and the focal length of the lens at that time. . A camera/lens system, comprising: a lens drive range control means that makes the range narrower than the first and second ranges stored in the storage means.