GB2256062A

GB2256062A - "device for controlling zooming during exposure"

Info

Publication number: GB2256062A
Application number: GB9210808A
Authority: GB
Inventors: Yutaka Ohsawa; Nobuhiko Matsudo
Original assignee: Asahi Kogaku Kogyo Co Ltd
Current assignee: Pentax Corp
Priority date: 1991-05-21
Filing date: 1992-05-21
Publication date: 1992-11-25
Also published as: FR2676828A1; DE4216914A1; JPH04348330A; GB9210808D0

Description

1 2 - b J 15 2 3 DEVICE FOR CONTROLLING ZOOMING DURING EXPOS SURE The

present invention relates to a device for carrying out a zooming during an exposure.

Conventionally, photographing by a zooming during an exposure is carried out in such a manner that a photographing lens, by which a zooming operation can be carried out, is mounted on a camera body, and at the same time as the shutter is released, the photographing lens is manually zoom-operated. In this case, the photographer must rotate the zoom ring of the photographing lens as smoothly as possible, while the shutter is open.

In such a manual exposure zooming operation, however, since it is difficult to rotate the zoom ring smoothly in the short time that the shutter is open, it is difficult to obtain a desired picture showing an effect of the zooming during an exposure.

Therefore, an object of the present is tO a device for controlling a zooming during an exposure, by which a photographing by a zooming during an exposure is carried out smoothly, whereby a desired picture showing an effect of the zooming during an exposure is easily obtained.

According to an aspect of the present invention, there is provided a device if for controlling a zooming during an exposure, the device comprising means for defining a program diagram, means for calculating an exposure value in accordance with a result of a photometry, means for setting a shutter speed and an aperture value in accordance with the exposure value and the program diagram, and a power zoom lens carrying out a zooming operation while the shutter is open, which zoom operation is controlled in accordance with the shutter speed and the aperture value. In the program diagram, a shutter speed has a value proper for a zooming during an exposure.

Further, according to another aspect of the present invention, there is provided a device for controlling a zooming during an exposure, the device rising a power zoam lens, reans for defining a prograra diagram, means for calculating an exposure value in accordance with a result of a photometry, means for setting a shutter speed and an aperture value in accordance with the exposure value and the program diagram, and means for controlling the power zoom lens to carry out a zooming operation, while the shutter is open, in accordance with the shutter speed and the aperture value set by the setting means. In the program diagram, a shutter speed is sufficient to all(... a zooming during an exposure.

Furthermore, according to a further aspect of the present invention, there is provided a device for controlling a zoom. lens, the control device comprising means for defining a program diagram for a zooming during an exposure, means for determining a shutter speed and an aperture value in accordance with the program diagram and an exposure value iw - 3 obtained in accordance with a result of a photometry, and means for controlling the zoom lens to carry out a zooming operation, while the shutter is open, in accordance with the shutter speed and the aperture value.

still further, according to a further aspect of the present invention, there is provided a device for controlling a zooming during an exposure, the device comprising reans for carrying out a photometry, Dieans for calculating an exposure value in accordance with a result of the photometry, means for calculating, in accordance with the exposure value, a shutter speed or an aperture value which is proper, for. a zooming during an exposure, and a power zoom lens carrying out a zooming operation while the shutter is open, which operation is controlled in accordance with the shutter speed and the aperture value.

The present invention will be better understood from the description of the preferred embodiments of the invention set forth below, together with the accompanying drawings, in which:

Figure 1 is a block diagram showing a cir-cuit of a camer-ca having a device for controlling a zooming during an exposure, in an embodiment of the present invention; Figure 2 is a timing chart showing an operation of the camera in a zooming during an exposure; Figure 3 is a diagram showing an example of a program diagram used in a zooming during an exposure; 0 0 Figure 4 is a flow chart of a main program; Figure 5 is a flow chart of a program line selecting process routine; Figure 6 is a flow chart of a program of a zooming during an exposure; and -Figure--7-is--&--diagram--showing--another example of-a-programdiagram used in a zooming during an exposure.

EmMles of the present invention will now be described with reference to embodiments shown in the drawings.

Fig. 1 shows a control circuit of a camera to which an embodiment of the present invention is applied. This control circuit includes a microconputer (CPU) 10 for carrying out a control of the whole of the camera, a microcomputer (DPU) 20 carrying out control of photometry and the like, a microcomputer (IPU) 30 controlling a display, and a microcomputer (lens CPU) 40 controlling a photographing lens. Among these microcomputers, only the lens CPU 40 is provided in the photographing lens; the other CPU's ape provided in a caniera body.

The CPU 10 carries out various kinds of sequence controls, an automatic focusing operation, a calculation for an exposure control, and so on. For carrying out these controls, the CPU 10 is connected to an EE circuit 11, a switch circuit 12, and motor, drive circuits 13 and 14. The EE circuit 11 generates a pulse signal, and a stcpping down operation is carried out in synchronization therewith.

of The switch circuit 12 is provided fop inputting a signal outputted by various switches, such as a photometry switch and a shuttet. release switch, to the CPU 10. The motor drive circuit 13 i.:-:, provided for driving a mechanical charge motor 15. The motor drive circuit 14 is provided for driving a film wind motor 16 and an automatic focusing motor 17. Further, the CPU 10 is connected to an E2PROM 18 storing information such as the number of frames of a film and various correction values, and to a plurality of magnets 19 provided for electrically holding the shutter in the closed position or releasing an engaged condition of the mirpor when tile shutter is to be opened.

The DPU 20 is connected to a CCD 21, which is a distance measurement sensor, and to a photometry IC 22 outputting a voltage signal corresponding to a luminance of an object. The DPU 20 carries out a photometry operation and acts as an interface with the CCD 21. The DPU 20 and the CPU 10 are respectively connected to a display (LED) 23 displaying various kinds of information in a view finder. The IPU 30 is connected to a display (LrD) 1, a flash 32 and a switch circuit 33. The LCD 31 is disposed on an outetsurface of the camera body and indicates various kinds (.-)f' information. The switch circuit 33 is provided for a selection of an exposure control in either a program mode or, a manual mode.

The lens CPU 40 is connected to the IPU 30 mounted in the camera body, and receives input information regarding a lens in % 0 which the lens CPU 40 is provided from the IPU 30, and outputs the information to the IPU 30, whereby the lens CPU 40 carries out various calculations in accordance with the information received. The lens CPU 40 is connected to a motor drive circuit 41 and a switch circuit 42. The motor drive circuit 41 is provided for driving a power zoom motor 43, to electrically drive the photographing lens for zoom operation. The switch circuit 42 is provided for, selecting one of a power zoom mode and a manual zoom mode and setting a mode in which a zooming during an exposure is to be carried out.

Fig. 2 is a timing chart showing an operation of the camera in a zooming during an exposure.

Referring to this timing chart, a shutter release button is pressed down whereby a shutter release switch is turned ON, and thus a mirror is moved up and a stop is set to a predetermined size. Then one of shutter blind magnets is de-energized, and thus a first shutter blind is moved as shown by the reference S1.

When a predetermined time has passed after the movement of the first shutter blind, the zoom motor 43 is driven as shown by the reference A. Then the other of the shutter blind magnets is de energized, and thus a second shutter blind is moved as shown by the reference S2. At the same time, the zoom motor 43 is stopped.

Accordingly, the rotation of the zoom motor 43 is started approximately midway during a period for which an exposure is carried out, whereby a zooming during an exposure is carried out. Namely, the zocmirxg eperation is carried out in the latter half of the period for which the shutter is open.

Fig. 3 is a program diagram used in a zooming during an exposure in the embodiment of the present invention.

In this diagram, a photographing is carried out generally at a shutter speed of 1/15 seconds (see the reference P1), which is slower than a usual shutter speed. This shutter speed is determined by test results obtained by taking actual photographs, and is a limit at which an effect of a zooming during an exposure is full-y apparent in a picture. That is, a shutter speed slower, than 1/15 Ls preferable, and a shutter speed of, for example, between 1/15 and 1/4 second, is proper for a zooming during an exposure.

Nevertheless, a photographing can not always be carried out at a shutter speed of 1/15 second. Namely, when an exposure value Ev is calculated in accordance with a result of a photometry and is larger than "13", which is too large, the aperture value Av is fixed to 1122'1 as an upper limit or maximum value (see the reference P2), and a photographing is carried out at a shutter speed corresponding to this maximum aperture value. Conversely, when an exposut-.e vC 1,-A,is obtained by a photometry and is smaller than "5", which is too small, the aperture value is fixed to 111. 411 as a lower, limit ot. minimum value (see the reference P3), and a photographing is carried out at a shutter speed corresponding to this minimurri aperture value.

Thus, the program diagram shown in Fig. 3 includes a line denoting a constant aperture value corresponding to the maxicrium aperture value and a line denoting a constant aperture value corresponding to the minimum aperture value. When the exposure value is between "T' and "13", a zooming during an exposure is carried out at a constant shutter speed of 1/15 second, and the aperture value is changed accordingly.

An operation of the embodiment is described below with reference to the flow charts shown in Figs. 4 through 6.

Fig. 4 shows a flow chart of a main program.

In Step 101, ports of the CPU 10 are initialized, and in Step 102, an automatic exposure (AE) is initialized, i.e., correction data necessary for a calculation of an exposure control is read from the E2PROM 18. Then, in Step 103, data necessary for an automatic focusing (AF) control is read from the E2PROM 18.

In Step 104, conditions of various switches, such as a photometry switch and a release switch, are read from the switch circuit 12. When the AF mode is currently set, an AF process is carried out in Step 105, and thus an AF control for the photographing lens is carried out.

In Step 106, it is determined whether or not 4 msec have elapsed since a predetermined time, and every time 4 msec have elapsed, the process goes from Step 106 to Step 107, and it is determined whether or not the release switch is turned ON. Namely, an ON-OFF condition of the release switch is checked every 4 msec, and when it is determined that the release switch is ON, a release 1 0 process is carried out. If it is determined at Step 106 that a time of 4 msec has not elapsed, then it is determined in Step 110 whether, or not 100 msec has elapsed since a predetermined time. Steps 1021 and 105 are executed when 100 msec have not elapsed, and Steps 111 through 113 are executed when 100 msec have elapsed.

In Step 111, predetermined data are transmitted from the IPU 30 to the CPU 10. This data, for example, comprises information indicating a kind of exposure mode, and information indicating whether a mode of the zoom lens is an electric mode (power zoom mode) or a manual mode. In Step 112, a photometry process is carried out, whereby an exposure value Ev is calculated based on photometry data, and a P-line selecting process routine (Fig. 5) and an ERP process routine (Fig. 6), which are described later, are executed. In Step 113, display data for the display (LCD) 31 is transmitted from the CPU 10 to the IPU 30, and this routine then returns to Step 104.

Fig. 5 shows a flow chart of a program line (P-line) selecting process routine.

When it is determined in Step 121 that the progt-am mode- ila- not been set, this routine is immediately ended. Conversely, when it is determined in Step 121 that the program mode has been set, the process goes to Step 122 and it is determined whether or not a power zoom lens is mounted on the camera body. In Step 123, it is determined whether or not a mode of the power zoom lens is set to the electric mode. In Step 124, it is determined whether, or not a - 10 mode for a zooming during an exposure (Ex zoom mode) is set. When the power zoom lens is mounted, the electric mode is set and the Ex zoom mode is set, the process goes to Step 125 and a flag for executing a program of the zooming during an exposure (EUP process routine, Fig. 6) is set. Conversely, when any one of the condtions determined in Steps 121 through 124 is not satisfied, this routine is ended without executing Step 125.

Fig. 6 shows a flow chart of a program for the EUP process routine.

In the following flow chart:- L0 corresponds to an exposure value Ev obtained in accordance with photometry data as described above, TvD corresponds to a shutter speed, and A0 corresponds to an aperture value. These LvD, TO and A0 have a relationship expressed by an equation of L0 = TO + AvD. Namely, LvD is an exposure value for calculation, TO is a shutter value for calculation, and A0 is an aperture value f(,P calculation. Lvd is determined in accordance with the photometry data, and then TO and AvD are determined in accordance with a program diagram shown in Fig. 3, for example.

In Step 131, a shutter speed for the zoomine during at, exposure EUM (time value Tv corresponding to 1/15 second, foc example) is set as TO. In Step 132, TO is subtracted from LvD, to thus obtain AvD.

Then, when it is determined in Step 133 that A0 is larger than AvDMAX, which is the maximum value of AvD, the process goes to t Step 134 in which AvD is made equal to AvDM. When it is determined in Step 135 that AvD is smaller than AvDMIN, which is the minimum value of AvD, the process goes to Step 136 in which MD is made equal to AvDMIN. When it is determined in Steps 133 and 135 that AvD is between AvDMAX and AvDMIN, this routine is iately ended.

When MD is wade equal to A in Step 134 or AvDMIN in Step 136, Step 141 is executed so that AvD is subtracted fram LvD, to obtain WD.

Then, when it is determined in Step 142 that W is larger than WDM, which is the maximum value of TvD, the process goes to Step 143 in which TvD is wade equal to T. When it is determined in step 144 that WD is smaller than TvDMIN, which is the minimum value of TvD, the process goes to Step 145 in which WD is made equal to TV.

When it is determined in Steps 142 and 144 that I'vD is between TOMAX and TvDMIN, this routine is immediately ended.

Thus, TvD and AvD are determined in accordance with the program diagram shown in Fig. 3.

As described above, in this embodiment, the zoorning during an exposure is carried out in such a manner that tht= shutter L usually set to, for example, 1/15 second, and the power zoom let-As is electrically driven while the shutter is open. Namely, the period for which the shutter is open is set to a value proper, for a zooming during an exposure, or as close thereto as possible, and the zooming operation is smoothly carried out by an electric control. Accordingly, a desired picture fully showing an effect of the zooming during an exposure can be obtained.

Note, although the line P1 of the shutter speed is fixed to 1/15 second in the program diagram of Fig. 3, this line PI can be inclined as shown in Fig. 7 so that a shutter speed is varied in accordance with an aperture value.

Although the embodiments of the present invention have been described herein with reference to the accompanying drawings, obviously many modifications and changes may be made by those skilled in this art without departing from the scope of the invention.

i

Claims

1. A device for controlling a zooming during an exposure, sa-W device comprising:

means for defining a program diagram in which a shutter speed has a proper value for the zooming during an exposure; il 0 means for calculating an exposure value in accordance with a result of a photometry; means for setting a shutter speed and an aperture value in accordance with said exposure value and said program diagram; and a power zoom lens carrying out a zooming operation while the shutter is open, which operation is controlled in accordance with said shutter speed and said aperture value.

2. A device according to claim 1, wherein said program diagram includes a line denoting a constant shutter speed.

3. A device according to claim 2, wherein said constant shutter, speed is between 1/ 15 through 1/

4 second. 4. A device according to claim 1, wherein said prograni diagrant includes a line denoting a varying of said shutter speed in accordance with said aperture value.

5. A device according to any one of the preceding claims, wherein said Program diagram further includes a line denoting a constant aperture value corresponding to a maximum aperture value.

6. A device according to claim 5, wherein said setting means sets said shutter speed to a maximum value when said shutter speed obtained in accordance with'said program diagram is larger than the 1 1- 0 maximum value.

7. A device according to any one of the preceding claims, wherein said program diagram further includes a line denoting a constant aperture value corresponding to a minimum aperture value.

8. A device according to claim 7, wherein said setting means sets said shutter speed to a minimum value when said shutter speed obtained in accordance with said program diagram is smaller than the minimum value.

9. A device for controlling a zooming during an exposure, sald device comprising:

a power zoom lens; means for defining a program diagram in which a shutter speed is sufficient to allow the zooming during an exposure; means for calculating an exposure value in accordance with a result of a photometry; means for setting a shutter speed and an aperture value in accordance with said exposure value and said program diagram; and means for controlling said power zoom lens to carry out a zooming operation, while the shutter is open, in accordance witli said shutter speed and said aperture value set by said settine. means.

10. A device for controlling a zoom lens, said control device comprising:

means for defining a program diagram for a zooming during an exposure; n means for determining a shutter speed and an aperture value in accordance with said program diagram and an exposure value obtained in accordance with a result of a photometry; and means for controlling said zoom lens to carry out a zooming operation, while the shutter is open, in accordance with said shutter speed and said aperture value.

11. A device for controlling a zooming during an exposure, said t If device comprising:

means for carrying out a photometry; means for calculating an exposure value in accordance with a result of the photometry; means for calculating, in accordance with said exposure value, a shutter speed or an aperture value which is proper for a zooming during an exposure; and a power zoom lens carrying out a zoot-riing operation while the shutter is open, which operation is controlled in accordance wil-h said shutter speed and said aperture value.

12. A device for controlling a zooming during an exposure, said device substantially as herein described with reference to the accompanying drawings.

13. A device for controlling a zoom lens, said control device substantially as herein described with reference to the accompanying drawings.