JPH11164177A - Digital still camera having lens system with finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely configure a photography optical system and a finder optical system, and to reduce electric power consumption at photography by providing an independent driving unit for the photography optical system and the finder optical system and bringing the driving unit under pulse control through the use of, for example, pulse motors. SOLUTION: Driving units for a photography optical system and a finder optical system are provided independently, and for example, pulse motors are used for the driving units to perform pulse control. In this camera, the photographic optical system moves a variator lens 2 and a focusing lens 4 forwards and backwards along an optical axis by the forward and reverse rotations of stepping motors 9 and 10. In the finder optical system, a stepping motor 23 forward and reverse rotates to move respective moving lenses 13 and 14 forwards and backwards along the optical axis for variable magnification. A driving and control circuit consists of motor drivers 25 and 27 which drive the stepping motors 9, 10, 23, and a microcomputer 29 and the like which controls the position of the moving lens group, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a digital still camera, and more particularly to a digital still camera having a lens system with a finder.

[0002]

2. Description of the Related Art In a conventional lens system with a real image type finder of a still camera of this type, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-64141, a zooming operation of a photographing optical system and a finder optical system are proposed. Various types have been proposed in which the zooming operation is mechanically linked with the zooming operation.

[0003]

However, in this type of conventional lens system with a finder, since the zooming operation of the photographing optical system and the zooming operation of the finder system are mechanically linked, There were the following problems.

1) The design layout of the photographing optical system and the finder optical system is limited.

2) A large driving force is required due to the mechanical interlocking mechanism, and the power consumption is increased.

[0006] The present invention has been made in view of the above-described aspects, and has as its object to provide means for solving these problems.

[0007]

SUMMARY OF THE INVENTION Therefore, in the present invention, the above object is achieved by providing a digital camera having a lens system with a finder according to any one of the following (1) to (4). Things.

(1) A photographing optical system and a finder optical system are provided. The photographing optical system and the finder optical system have independent lenses and drive mechanisms, respectively, and perform independent drive control. A digital still camera having a lens system with a finder characterized by the following.

(2) In the lens system, each moving lens group of the photographing optical system and the finder optical system includes:
A digital still camera having a system with a finder as described in the above item (1), having each position detecting means, and performing electrically linked control and independent driving and control.

(3) Only the finder optical system is driven during the zoom operation of the lens system, and only at the time of photographing, the photographing optical system is zoomed to a zoom position where the field of view of the finder optical system is substantially the same. 3. The digital still camera with a finder according to any one of the above (1) and (2), wherein:

(4) The digital still camera with a finder according to the above (3), wherein, at the time of photographing with the lens system, the photographing optical system carries out photographing by performing magnification and focusing.

[0012]

According to the above-described structure of the present invention, the following effects can be obtained: (1) The driving devices of the photographing optical system and the finder optical system are made independent, and the driving devices are provided with, for example, By using a pulse motor and performing pulse control, 1) the telephoto end of each of the photographing optical system and the finder optical system,
Since the position of the moving lens group, such as the wide-angle end, is controlled by the number of steps from each sensor, the adjustment of the relative relationship between the two optical systems is
It can be easily performed only by changing the number of steps.

2) The layout of the photographing optical system and the finder optical system can be freely designed.

(2) Further, the photographing optical system is not moved until the shutter button is pressed, and the photographing angle of view is determined by zooming of the photographer by controlling only the viewfinder optical system. Can reduce consumption.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
A preferred embodiment will be described in detail with reference to the drawings.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Structure) FIG. 1 is a schematic structural diagram of a photographing optical system, a finder optical system, and respective drive mechanisms and control value circuits according to an embodiment of the present invention.

The photographing optical system includes a field lens 1, a variator lens 2, an afocal lens 3, and a focus lens 4, and the variator lens 2 and the focus lens 4 are respectively mounted on respective lens frames 7, 8. It is held and is guided along the guide bars 5 and 6 so as to be able to advance and retreat in the optical axis direction.

Rack portions 7a, 7a,
8a and the threaded rod portions 9a and 10a of the stepping motors 9 and 10 which are the driving sources are connected to each other by urging means (not shown).
The variator lens 2 and the focus lens 4 respectively move forward and backward in the optical axis direction when the stepping motors 9 and 10 rotate forward / reversely without play.

The respective initial positions of the variator lens 2 and the focus lens 4 are detected by the respective photointerrupters 11, in which a light emitting element and a light receiving element are integrated.
12 is detected when the light shielding members 7b and 8b provided on the movable lens frame pass.

On the other hand, the finder optical system includes each moving lens 1.
3, 14, a field lens 15, and a prism 16
And an eyepiece 17, and each movable lens 13,
Reference numeral 14 is held by each of the lens frames 20 and 21 and is guided along the respective guide bars 18 and 19 so as to be able to advance and retreat in the optical axis direction.

The convex portions 20a and 21a provided on the lens frames 20 and 21 respectively contact the cam grooves 22a and 22b of the cam ring 22, and the gear portion 22c of the cam ring 22 and the gear reducer 23a The output gear 23b of the stepping motor 23 having the gears meshes with each other.
Moves forward and backward in the optical axis direction to perform zooming.

The initial position of the cam ring 22 is detected when the light interrupting member 22d provided on the cam ring 22 passes through the photo interrupter 24.

The drive / control circuit controls each motor driver 25, 26, 27 for driving each stepping motor, an image processing device 28 for processing a video input from an image pickup device (CCD) 31, and a position control of a moving lens group. Microcomputer 29 to perform
Switch 3 for inputting the direction of telephoto and wide-angle
0, a shutter button 32 and the like.

The positions of the telephoto end and the wide-angle end with respect to the initial position of the variator lens 2 of the photographing optical system are stored in the internal storage device of the microcomputer 29 of FIG. 1 in the number of steps corresponding to the rotation amount of the stepping motor 9. ing.

The position data determined by the distance and the position of the variator with respect to the initial position of the focus lens 4 is stored in the number of steps corresponding to the rotation amount of the stepping motor 10. That is, the zooming operation of the photographing optical system is controlled by a rear focus zoom electronic cam system generally used in video cameras.

After the main photographing optical system and the finder optical system are mechanically fixed and the field ratio of the finder optical system to the photographing optical system is adjusted, the cam ring 22 of the finder optical system is adjusted.
The adjusted positions of the telephoto end and the wide-angle end with respect to the initial position are stored in the internal storage device of the microcomputer 29 by the number of steps corresponding to the rotation amount of the stepping motor 23.

(Operation) FIG. 2 is a flowchart showing an operation sequence of the digital still camera according to the present embodiment having the above configuration.

In the lens system with a finder constructed as in this embodiment, the variator lens 2 and the focus lens 4 of the photographing optical system are turned on when the power of the camera body is turned on.
And the cam ring 22 of the finder optical system respectively perform initial position setting (steps S1 and S2), and each moving lens group stands by at an arbitrary position substantially at the center of each moving stroke (step S3).

At this point, if the photographer presses the shutter button (SW) 32 in step S4, the focus lens 4 of the photographing optical system moves to the in-focus position in step S5, focuses in step S6, and captures an image in steps. Element (CCD) 31
Is input to the image processing device 28 and stored in the memory 3.
3 and the process returns to step S3.

On the other hand, if the photographer is performing zooming without pressing the shutter button 32 in step S4 (step S8), only the finder optical system is driven. After the photographer determines the angle of view at an arbitrary zoom position through step S10 or S12 according to the classification of wide → tele (step S9) or tele → wide (step S11), the shutter button 32 is set at step S4.
When the button is pressed, the variator lens 2 of the photographing optical system moves to a zoom position having the same field of view as the finder optical system based on the data of the microcomputer 29, and furthermore, the focus lens 4 moves to the focus position. After focusing, the video input of the image sensor 31 is taken into the image processing device 28 and recorded in the memory 33.

Immediately thereafter, unless the shutter button 32 is further pressed, the variator lens 2 and the focus lens 4 of the photographing optical system return to the above-mentioned arbitrary standby positions (step S3).

In the present embodiment, an optical system capable of performing a focus operation on the photographing optical system is used. However, a pan-focus optical system for only zooming may be used.

[0033]

As described above, according to the present invention,
By making each driving device of the photographing optical system and the finder optical system independent and performing pulse control using, for example, a pulse motor for each of the driving devices, 1) the telephoto end of each of the photographing optical system and the finder optical system;
Since the position of the movable lens group at the wide angle end is controlled by the number of steps from each sensor, the adjustment of the relative relationship between the two optical systems can be easily performed only by changing the number of steps.

2) The layout of the photographing optical system and the viewfinder optical system can be freely designed.

Further, the photographing optical system is not moved until the shutter button is pressed, and the photographing angle of view is determined by zooming of the photographer by controlling only the viewfinder optical system. 3) Electricity consumption during photographing can be reduced. And other effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a drive mechanism and a control circuit according to an embodiment.

FIG. 2 is an operation sequence flowchart from power-on of the camera of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Field lens 2 Variator lens 3 Afocal lens 4 Focus lens 5, 6, 18, 19 Guide bar 7, 8, 20, 21 Moving lens frame 9, 10, 23 Stepping motor 11, 12, 24 Photo interrupter 13, 14, Viewfinder Moving lens 15 Field lens 16 Prism 17 Eyepiece 22 Cam ring 25, 26, 27 Motor driver 28 Image processing device 29 Microcomputer 30 Zoom switch 31 CCD 32 Shutter button 33 Memory

Claims (4)

[Claims] An imaging optical system and a finder optical system are provided. Each of the imaging optical system and the finder optical system has an independent lens and a driving mechanism, and performs independent driving control. A digital still camera having a lens system with a finder. 2. In the lens system, each moving lens group of the photographing optical system and the finder optical system has a respective position detecting means, and performs electrically linked control and independent driving and control. 2. The method according to claim 1, wherein
A digital still camera having the system with a finder as described. 3. The lens system drives only the finder optical system during a zoom operation, and only during photographing, the photographing optical system zooms to a zoom position at which the field of view of the finder optical system is substantially the same, so that photographing is performed. The digital still camera with a finder according to claim 1, wherein the digital still camera is operated. 4. The digital still camera with a finder according to claim 3, wherein, at the time of shooting with said lens system, said shooting optical system performs zooming and focusing to shoot.