JPH03236024A - Camera with inter-exposure zooming function - Google Patents

Abstract

PURPOSE:To make the variation rate of focal length at the time of zooming constant and to obtain a smooth photographic picture by comparing focal length, detected by a focal length variation detecting means with a preset focal length variation rate and controlling the rotating speed of a zoom motor according to the comparison result. CONSTITUTION:When the zoom motor is driven to start exposure and inter- exposure zooming is carried out, a focal length variation detecting means 49 detects the focal length in the zooming. The focal length detected by the focal length variation detecting means 49 is stored in a memory means 45 and compared by a comparing means 53 with the previously set focal length variation rate. A motor speed control means 47 controls the rotating speed of the zoom motor 4 according to the comparison result of the comparing means 53 so that the focal length variation rate in the zooming comes to constant. In the inter-exposure zooming, the smooth photographic image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a camera having a power zoom function that drives a zoom lens by driving a zoom motor.

"Prior art and its problems" Inter-exposure zooming is a photographic technique that uses the variable focus mechanism, which is a characteristic of zoom lenses, to consciously move the focus during exposure, aiming for expressive effects such as a sense of motion. Since this inter-exposure zooming is performed within the exposure time, it is generally used in combination with a slow shutter.

In an electric zoom lens that uses power for zooming, this zooming during exposure can be performed relatively easily. By the way, in a zoom lens that is zoomed by a zoom motor, even if the rotation speed of the zoom motor is constant, the rotation is transmitted through a cam groove, etc., so the rate of change in focal length during zooming is constant. do not become. For this reason, problems such as the imprinted image not being smooth may occur.

``Object of the Invention'' The present invention has been made in view of the above-mentioned conventional problems, and allows zooming between exposures to be performed with a simple operation, while keeping the rate of change of focal length constant during zooming.
The purpose is to obtain smooth captured images.

"Summary of the Invention" The present invention provides: a zoom motor that drives a zoom lens; an during-exposure zoom starting means that drives the zoom motor based on the operation of the zoom motor, starts exposure, and starts during-exposure zooming; Focal length change detection means for detecting a changing focal length; comparison means for comparing the focal length detected by this focal length change detection means with a preset focal length setting change rate; and based on the comparison result by this comparison means, A motor speed control means for controlling the rotational speed of the zoom motor in order to keep the focal length change rate constant during zooming.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIG. 2 is a side view of the camera 10 to which the present invention is applied, and FIG. 3 is a plan view thereof.

The camera IO has a camera body 12, a zoom lens 13 is attached to the center of the front surface of the camera body 12, and the right side of the front surface protrudes forward to serve as a grip portion 14. A release button 15 is provided above the grip portion 14, and a mode changeover switch 16 for switching the mode of the camera is provided adjacent to the release button 15.

As shown in FIG. 4, the zoom lens 13 has an outer fixed lens barrel 17, a cam ring 19, and a lens 18. A plurality of zooming cam grooves 21 are formed in the cam ring 19, and a gear surface 60 is provided. A pinion gear 61 rotated by the zoom motor 4 meshes with this gear surface 60. The rotation of the lens 18 is restricted by the outer fixed TFJ barrel 17, and the lens 18 is supported so as to be movable only in the optical axis direction. A code plate 22 (see FIG. 7) is attached to the outer peripheral surface of the cam ring 19, and a code plate brush 28 is in contact with the code plate 22. When the cam ring 19 rotates due to the rotation of the zoom motor 4, the lens 18 is moved forward and backward along the zooming cam groove 21 in the optical axis direction. At this time, the focal length is read by the code plate brush 28.

The outer fixed lens barrel 17 has a wide button 29, a tele button 30, a start button 31, a memory button 32, and a Pz (power zoom) mode changeover switch 33, as shown in FIGS. 2 and 3. .

As shown in FIGS. 5 and 6, the wide button 29 and the tele button 30 are each visible, and conductive contact pieces 29a and 3 are provided at positions facing the operation input board (see FIG. 8).
It has 0a. Therefore, when the wide button 29 is pressed, the conductive contact piece 29a and when the tele button 30 is pressed, the conductive contact piece 30a is configured to electrically contact the operation input board 35 and turn on. .

Pz mode selector switch 33 is Pz (power zoom)
mode and Exz (exposure zoom) mode, by sliding the Pz mode selector switch 33 in the left and right direction in FIG.
The code plate brush 40 is brought into contact with the operation input board 35 to switch.

A control circuit for a camera 10 having an during-exposure zooming function according to the present invention will be explained with reference to FIG.

The control unit 1 includes, on its input side, a release button 15, a wide button 29, a tele button 30, a Pz mode changeover switch 33, a mode changeover switch 16, a code board brush 28 that comes into contact with the code board 22, a memory button 32, and a start button. A button 31 and a shutter dial 51 are connected. Further, a zoom motor 4 and a solenoid 5 (exposure operating means) for operating a shutter are connected to the output side of the control unit 1.

The control unit 1 includes a zooming start means 8, a zooming end means 24, a count means 14, an exposure start means 9, a Pz mode switching means 6, a mode switching means 7, a focal length change detection means 49, a focal length memory means 45, and a shutter speed. It has reading means 50, exposure control means 46, comparison means 53, and motor speed control means 47.

The zooming start means 8 is a wide button 29 or a tele button 30.
Based on the input signal from the zoom motor 4, the zoom motor 4 is driven via the motor speed control means 47 to start zooming.

The counting means 14 starts counting in synchronization with the start of zooming by the zooming starting means 8.

The zooming termination means 24 stops driving the zoom motor 4 when the count value by the counting means 14 reaches a certain value for the shutter speed read by the shutter speed reading means 50.

The exposure starting means 9 outputs a signal to the solenoid 5 to start exposure when a predetermined time period that is set in advance has elapsed from the start of counting by the counting means 14.

The Pz mode switching means 6 is a Pz mode switching switch 33.
The mode is switched based on the input signal from the

The mode switching means 7 switches the mode to, for example, a self-timer mode based on an input signal from the mode switching switch 16.

The focal length change detection means 49 receives the code read from the code plate 22 by the code plate brush 28 and detects a change in focal length during zooming.

The focal length memory means 45 stores the focal length f1 at the end of zooming at the position where zooming ends, and the focal length f2 at the start of zooming at the position where zooming starts.
to memory.

The shutter speed reading means 50 uses the shutter dial 5
Read the shutter speed set by 1.

Exposure control means 46 receives a signal from shutter speed reading means 50 and controls exposure.

The comparison means 53 compares the focal length detected by the focal length change detection means 49 with a preset focal length setting change rate C.

The motor speed control means 47 controls the rotation speed of the zoom motor 40 to keep the change in focal length constant during zooming based on the comparison result by the comparison means 53.

Next, the operation of the camera IO having the during-exposure zooming function will be explained with reference to FIGS. 9 to 12.

When the release button 15 is pressed halfway to turn on the photometry switch in step S1, it is checked in step S2 whether zooming during exposure is to be performed. If zooming during exposure is to be performed, proceed to step S3; if not, proceed to step S4.
Proceed to.

Here, the shutter speed is set by operating the shutter dial 51.

In step S3, it is checked whether the TV value (shutter speed) is slower than the X contact synchronization speed (strobe synchronization speed). As a result, if the shutter speed is faster than the X contact synchronization speed, step S2 is repeated, and if it is slower, the process proceeds to step S5.

In step S5, the TV value B set with the shutter dial 51 is read into the shutter speed reading means 50, and the process proceeds to step S6.

In step S6, 0N10FF of the wide button 29 is checked. If it is turned on, the process advances to step S7, where the zoom motor 4 is driven, and the process exits to step S3. If the wide measurement 29 is set to F, the process advances to step S8.

In step S8, 0N10FF of the tele button 30 is checked. As a result, if the telephoto side button 30 is turned on, the process proceeds to step S7, and if it is turned off, the process proceeds to step S9.

In step S9, the focal length fl at the end of zooming is read into the focal length memory means 45, and the process proceeds to step SIO.

In step SIO, 0N10FF of the start button 31 is checked. As a result, if the start button 31 is not turned on, the process returns to step S5, and if it is turned on, the process proceeds to step Sll.

In step Sll, 0N10FF of the wide button 29 is checked. As a result, if it is turned on, step S1
4, and if it is not turned on, step S13
Proceed to.

In step S13, 0N10FF of the tele button 30 is checked. As a result, if it is not turned on, step S
1 is repeated, and if it is turned on, the process advances to step S14.

In step S14, the zooming direction is read, and the process advances to step S15.

In step S15, the zooming start means 8 starts driving the zoom motor 4, and the process proceeds to step S16.

In step 316, the exposure start means 9 operates the release switch to generate a release signal, and the process proceeds to step S17.

In step S17, the focal length change read into the focal length detection means 49 is monitored, and the focal length f2 at the start of zooming is read, and the process proceeds to step S18.

In step 318, Δf is calculated, and the process proceeds to step S19.

In step S19, the counting means 14 counts the time t and calculates Δf/Δt.

In step 326, the comparing means 53 performs step S19.
Δf/Δt calculated in step 1 is compared with a preset focal length setting change rate C. As a result, if Δf/Δt>C, the process proceeds to step S27, and the motor speed control means 47 lowers the rotational speed of the zoom motor 4. Further, if Δf/Δt<C, the process proceeds to step S2g, and the rotational speed of the zoom motor 4 is increased by the motor speed control means 47.

In step S29, it is checked whether the 2C switch (a switch set to be turned on when the trailing curtain of the focal brain shutter completes travel) is turned on. As a result, if it is not turned on, the process returns to step S17, and if it is turned on, the process goes to step S30.

In step S30, the zoom motor 4 is stopped, and the process returns to step S31.

On the other hand, in step S4, the wide button 29 is set to 0N10.
Check FF. As a result, if it is turned on, the process advances to step S20 to drive the zoom motor 4, and if it is not turned on, the process advances to step S21.

In step S21, 0N10FF of the tele button 30 is checked. If it is turned on, the process advances to step S20 to drive the zoom motor 4, and if it is not turned on, the process advances to step S22.

In step S22, the release switch is set to 0N10FF.
is checked, and if it is not turned on, step S4 is repeated; if it is turned on, the process advances to step S23.

In step S23, the exposure starting means 9 generates a release signal, and the process proceeds to step S24.

In step S24, 0N10FF of the 2CS switch is checked, and if it is not turned on, step S24 is repeated, and if it is turned on, the process advances to step S25 and returns.

"Effects of the Invention" As described above, the camera having the during-exposure zooming function of the present invention can automatically perform the during-exposure zooming simply by turning on the zooming start means. It can be done easily and reliably without relying on intuition. Furthermore, since the rotation speed of the zoom motor can be controlled by comparing the focal length that changes during zooming with a preset focal length setting change rate, the change rate of the focal length during zooming can be kept constant.
You can obtain smooth captured images.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a control circuit of a camera having an during-exposure zoom function according to the present invention, Fig. 2 is a side view showing the external appearance of this camera, Fig. 3 is a plan view thereof, and Fig. 4 shows a zoom lens. 5 is a partially enlarged front sectional view showing the main parts of the zoom lens, FIG. 6 is an enlarged sectional view showing the structure of the Pz mode changeover switch, and FIG. 7 is an enlarged sectional view showing the structure of the Pz mode changeover switch. FIG. 8 is an enlarged view of the code plate, FIG. 8 is an enlarged view of the operation input board, and FIGS. 9 to 12 are flow charts showing the operation of this embodiment. 4... Zoom motor, 8... Zooming start means,
9... Exposure start means, 13... Zoom lens, 29
．． 30... Wide button, tele button (during exposure zooming start means), 47... Motor speed control means, 49... Focal length change detection means, 53... Comparison means, C... Focal length setting Rate of change.

Claims (1)

[Claims] (1) A zoom motor that drives the zoom lens; An during-exposure zoom starting means that drives the zoom motor based on its operation to start exposure and start during-exposure zooming; detects the changing focal length of the zoom lens; Focal length change detection means; Comparison means for comparing the focal length detected by this focal length change detection means with a preset focal length setting change rate; and Based on the comparison result by this comparison means, focal length change detection means during zooming. 1. A camera having an during-exposure zooming function, comprising: a motor speed control means for controlling the rotational speed of the zoom motor to keep the zoom ratio constant;