JP2727610B2 - Camera focal length control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a focal length control device for a camera having a zoom lens.

B. Conventional Art Conventionally, a camera that performs zooming by electric power is known. That is, this type of camera has a zoom-up button and a zoom-down button. The zoom-up button is operated to electrically drive the focal length of the zoom lens to the telephoto side, and the zoom-down button is operated to move the focal length to the wide-angle side. Electrically driven.

C. Problems to be Solved by the Invention By the way, in this type of zoom camera, the frequency of photographing by driving the zoom lens to one of the wide-angle end, the telephoto end, and almost the intermediate position (intermediate focal length) is usually high. Relatively high. For example, a camera provided with a zoom lens having a variable focal length in the range of 35 mm to 70 mm frequently shoots at 35 mm, 50 mm, and 70 mm.

However, in a conventional zoom camera in which the focal length of the zoom lens is not displayed at all, the value of the focal length cannot be confirmed when the zoom lens is driven to an intermediate position. Therefore, for example, some cameras sequentially display the focal length of the zoom lens using a liquid crystal display device or the like.However, when driving the zoom lens to an intermediate focal length, the user zooms in to a predetermined focal length while watching the display. The button or the zoom-down button must be operated, and the operability is poor.

A technical object of the present invention is to make it possible to easily drive a zoom lens to an intermediate focal length where the frequency of driving the zoom lens is relatively high.

D. Means for Solving the Problems To be described with reference to FIG. 1 showing an embodiment, the present invention relates to a zoom lens LE and a method of driving the zoom lens LE between a telephoto end position and a wide angle end position. Driving means 3 and 4 for changing the focal length, and driving means 3 and 4 for changing the focal length of the zoom lens LE to the telephoto side in accordance with the first operation, and the zoom lens in accordance with the second operation The present invention is applied to a focal length control device for a camera including a control unit 1 for controlling the driving units 3 and 4 to change the focal length of the LE to the wide angle side.

Then, the control unit 1 controls the driving units 3 and 4 to change the focal length of the zoom lens LE to a preset intermediate focal length between the telephoto end position and the wide angle end position in accordance with the third operation. The present invention solves the above-mentioned problems.

The invention according to claim 2 includes a zoom-up operation member 5 and a zoom-down operation member 6, wherein the zoom-up operation member 5 is provided.
The focal length of the zoom lens LE is changed to the telephoto side with the operation of the zoom lens LE, and the focal length of the zoom lens LE is changed to the wide-angle side with the operation of the zoom-down operation member 6. When it is detected that are operated at the same time, the driving means 3 and 4 are controlled to change the focal length of the zoom lens LE to the intermediate focal length.

E. Operation The control means 1 controls the driving means 3 and 4 in accordance with the third operation to set the focal length of the zoom lens LE to an intermediate focal length preset between the telephoto end position and the wide angle end position. change.

In the above sections D and E for describing the configuration of the present invention, the drawings of the embodiments are used for easy understanding of the present invention, but the present invention is not limited to the embodiments.

F. Embodiment An embodiment of the present invention will be described with reference to FIGS.

In FIG. 1 showing the overall configuration, an encoder 2, a motor drive circuit 3, and switches ZUS and ZDS are connected to a CPU1. The encoder 2 detects the focal length of the zoom lens LE and inputs it to the CPU 1. The switches ZUS and ZDS are switches that are turned on in conjunction with the operations of the zoom-up button 5 and the zoom-down button 6, respectively.

A zooming motor 4 is connected to the motor driving circuit 3, and the zoom lens LE is driven by the motor 4 in response to a zooming signal from the CPU 1 to be described later to change the focal length. Here, it is assumed that the camera of this embodiment includes a zoom lens LE having a variable focal length in a range of 35 mm (wide-angle end position) to 70 mm (telephoto end position). The above-described zooming signal is output to the CPU 1 based on the switches ZUS and ZDS being turned on.
And is output to the motor drive circuit 3. And
While the switch ZUS is on by operating the zoom-up button 5, the focal length of the zoom lens LE changes to the telephoto side (zoom up), and the zoom is performed while the switch ZDS is on by operating the zoom-down button 6. The focal length of the lens LE changes to the wide angle side (zoom down).

When the switches ZUS and ZDS are simultaneously turned on, the CPU 1 detects the zoom lens detected by the encoder 2 described above.
Control for driving the zoom lens LE to a predetermined focal length is performed based on the focal length of the LE. The predetermined focal length is an intermediate focal length set in advance between the telephoto end position and the wide-angle end position, and in this embodiment, the intermediate focal length is
It is assumed that it is set to 50 mm.

In the configuration of the above embodiment, the motor drive circuit 3 and the zooming motor 4 constitute drive means, the CPU 1 constitutes control means, and the buttons 5 and 6 constitute zoom-up operation members and zoom-down operation members.

Next, based on the flowcharts of FIGS.
The following describes a zooming control procedure according to the embodiment.

When the zoom-up switch ZUS is turned on, the program shown in FIG. 2 is started. First, in step S1, the motor driving circuit 3 is turned on.
Then, a zooming signal is output, and the zoom lens LE is driven by the motor 4 to change its focal length to the telephoto side.
That is, zoom up is started. Next, in step S2, it is determined whether or not the switch ZUS is still on, and if affirmative, it is determined in step S3 whether or not the switch ZDS is on. If step S3 is negative, it is determined from the output of the encoder 2 in step S4 whether the focal length f is 70 mm, that is, whether the zoom lens LE has been driven to the telephoto end position.

If step S4 is denied, the process returns to step S2, and if affirmed, the zoom lens LE is stopped in step S5. Next, in step S6, it is determined whether or not the switch ZUS is still on. If the result is affirmative, the process waits until the result is negative. If step S2 is denied, the process proceeds to step S5.

On the other hand, after the start of zoom-up, if step S3 is affirmed, that is, if it is determined that both the switch ZUS and the switch ZDS are on, step S1 in FIG.
Proceed to 1. In step S11, the detection result of the encoder 2 is read, and then in step S12, the current zoom lens LE is read.
Is compared with 50 mm. If f ≧ 50 mm, the process proceeds to step S13, in which the zoom lens LE is driven by the motor 4 via the motor drive circuit 3 in the opposite direction to the above, and the focal length f is changed to the wide angle side. That is, the mode is switched from zoom up to zoom down, and thereafter, the process proceeds to step S14. If f <50 mm is determined in step S12, the process directly proceeds to step S14.

In step S14, it is determined whether or not the current focal length of the zoom lens LE is 50 mm from the detection result of the encoder 2, and if negative, the process proceeds to step S15. In steps S15 and S16, the state of the switches ZUS and ZDS is determined, and if both are on, the process returns to step S14. Step S
If affirmative, the zoom lens LE is stopped in step S17, and the switches ZUS and ZD are switched in steps S18 and S19.
It waits until it is determined that both S have been turned off, and then ends the processing.

If step S16 is denied, that is, if the switch ZUS is on and the switch ZDS is off, the process returns to step S1 in FIG. 2 described above. Further, if step S15 is denied, it is determined in step S20 whether or not the switch ZDS is on. When step S20 is denied, that is, when both the switch ZUS and the switch ZDS are off, the process is terminated. The process proceeds to step S31 in FIG.

The program in FIG. 4 is started when the switch ZDS is turned on. First, in step S31, the motor 4 is started to zoom-down via the motor drive circuit 3. Next, in step S32, it is determined whether or not the switch ZDS is still on, and if affirmative, it is determined in step S33 whether or not the switch ZUS is on. If step S33 is negative, it is determined from the output of the encoder 2 in step S34 whether the focal length f is 35 mm, that is, whether the zoom lens LE has been driven to the wide-angle end position.

When step S34 is denied, the process returns to step S32, and when affirmed, the zoom lens LE is stopped in step S35.
Next, in step S36, it is determined whether or not the switch ZDS is still on. If the result is affirmative, the process waits until the result is negative. If step S32 is denied, the process proceeds to step S35.

On the other hand, if step S33 is affirmed, that is, if it is determined that both the switch ZUS and the switch ZDS are on after the start of zoom-down, the process proceeds to step S37. In step S37, the detection result of the encoder 2 is read, and then in step S38, the current focal length f of the zoom lens LE is compared with 50 mm. Step if f <50mm
Proceeding to S39, zoom-up is started by the motor 4 via the motor drive circuit 3, and thereafter, at step S14 in FIG.
Proceed to. If f ≧ 50 mm, it means that the zoom is currently down, and the process directly proceeds to step S14.

According to the above procedure, when only the zoom up button 5 is operated, the switch ZUS is turned on to perform zoom up, and when only the zoom down button 6 is operated, the switch ZDS is turned on and zoom down is performed. When both buttons 5 and 6 are simultaneously operated, switches ZUS and ZDS are both turned on, and accordingly, the focal length of zoom lens LE is changed to 50 mm. As in the present embodiment, in a camera having a zoom lens whose focal length is variable in the range of 35 mm to 70 mm, the frequency of shooting at 35 mm, 50 mm, and 70 mm is relatively high, and according to the above-described procedure, 35 mm, 7
The zoom lens can be easily guided not only to 0 mm but also to the middle 50 mm.

In the above embodiment, the single operation of the zoom amplifier button 5 corresponds to the first operation, the single operation of the zoom down button 6 corresponds to the second operation, and the simultaneous operation of the buttons 5 and 6 corresponds to the third operation.

The present invention can be applied to a camera provided with a zoom lens having a variable focal length in a range other than 35 mm to 70 mm, and the intermediate focal length is not limited to 50 mm.

In the above description, the zoom lens is guided to the intermediate focal length by pressing the buttons 5 and 6 at the same time. However, if the buttons 5 and 6 are simultaneously operated once, the intermediate focal length is obtained even if the hand is released thereafter. The zoom lens may be driven first.

Furthermore, a desired intermediate focal length may be set by operating the operation member, and when the buttons 5 and 6 are operated simultaneously, the zoom lens may be guided to the set focal length.

G. Effects of the Invention According to the present invention, with the third operation different from the first operation (zoom-up operation) and the second operation (zoom-down operation), the focal length of the zoom lens is set to the telephoto end position. Since the intermediate focal length is changed to a preset intermediate focal length between the wide-angle end position, the photographing lens can be guided to the frequently used intermediate focal length by a simple operation without confirmation on a display device or the like, Operability is improved.

[Brief description of the drawings]

1 to 4 show an embodiment of the present invention, and FIG.
FIG. 2 is a block diagram showing a focal length control device for a camera according to the present invention, and FIGS. 2 to 4 are flowcharts each showing a processing procedure. 1: CPU, 2: Encoder 3: Motor drive circuit, 4: Zooming motor 5: Zoom up button, 6: Zoom down button LE: Zoom lens

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Daitoku 1-6-3 Nishioi, Shinagawa-ku, Tokyo Inside Nikon Oi Works Co., Ltd. (72) Inventor Toshiyuki Nakamura 1-3-6 Nishioi, Shinagawa-ku, Tokyo Nikon Oi Manufacturing Co., Ltd. (56) References JP-A-62-265632 (JP, A)

Claims (2)

(57) [Claims] A zoom lens; driving means for driving the zoom lens between a telephoto end position and a wide angle end position to change a focal length thereof; and a telephoto focal length of the zoom lens in accordance with a first operation. And a control means for controlling the driving means to change the focal length of the zoom lens to a wide angle side in response to a second operation. In the above, the control unit controls the driving unit to change the focal length of the zoom lens to an intermediate focal length set in advance between the telephoto end position and the wide angle end position in accordance with a third operation. A focal length control device for a camera. A zoom-up operation member and a zoom-down operation member, wherein the control means changes a focal length of the zoom lens to a telephoto side in accordance with an operation of the zoom-up operation member, and controls the zoom-down operation member. Accordingly, the focal length of the zoom lens is changed to the wide angle side, and when it is detected that the zoom-up operation member and the zoom-down operation member are simultaneously operated, the focal length of the zoom lens is changed to the intermediate focal length. 2. The focal length control device for a camera according to claim 1, wherein the driving unit is controlled to control the focal length.