JPS6259941A - Still camera - Google Patents

Abstract

PURPOSE:To perform continuous fast photography not by returning by stop to a full-open position every time exposure is performed once in continuous photography, but by opening the stop only for a specific time after the exposure is completed. CONSTITUTION:When the exposure is completed, the top 4 begins to be opened and a counting circuit 9 counts the time that the stop 4 requires to be opened until a finder (not shown in figure) reaches brightness where there is no practical problem; when the counting of the time is completed, a stop opening operation stop signal is sent to a stop control circuit 3 and the opening operation of the stop is stopped. Therefore, the stop is not always opened to its opening position according to the stop position in the exposure. Simultaneously, a shutter 7 and a movable mirror 5 are charged and after the charging, the stop 4 is reduced in opening extent and a mirror is hopped up, so that continuous photography is carried out by a series of operations.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a still camera capable of high-speed continuous shooting.

2. Description of the Related Art FIG. 3 shows an example of the configuration of a conventional still camera. Fourth
The figure is a timing diagram showing an example of the mechanical operating state of each part during continuous shooting of a conventional still camera.
(b) shows the operating state of the aperture, (C) shows the operating state of the movable mirror, (d) shows the operating state of the front curtain magnet, and (e) shows the operating state of the rear curtain magnet 2.
Indicates the operating status of the

This conventional example will be explained below with reference to FIGS. 3 and 4. As shown in FIG. 4(a), when the release button 1 is pressed, aperture information is sent from the system control circuit 2 to the aperture control circuit 3, and the aperture 4 is set to photometry as shown in FIG. 4(0)). The aperture value will be narrowed down to the base aperture value or a preset aperture value. At the same time as the aperture 4 is closed down, the movable mirror 6 is raised as shown in FIG. 4(C). When the aperture 4 has been stopped down, a front curtain start signal is sent from the system control circuit 2 to the shutter drive circuit 6, and the front curtain of the shutter 7 (not shown) is activated as shown in FIG. 4(d).
is opened, and the imaging surface is exposed to light (hereinafter simply referred to as exposure).

After the shutter 7 is opened, when the shutter time based on photometry or the preset shutter time t has elapsed, the shutter drive circuit 6 is activated from the system control circuit 2.
A trailing curtain start signal is sent to the shutter 7, and the trailing curtain (not shown) of the shutter 7 closes as shown in FIG. 4(e). When the exposure is completed, the aperture 4 is returned to the open position, and the shutter 7 and movable mirror 5 are set to their initial states (hereinafter referred to as
charge). In the continuous shooting mode, when charging and opening of the aperture 4 are completed, the aperture 4 is stopped down again and the mirror is raised, and continuous shooting is performed by the series of operations described above.

Note that 8 is a lens optical system.

Problems to be Solved by the Invention However, as described above, in the method of returning the diaphragm 4 to the open position for each exposure, the time t1 for the diaphragm 4 to open from the stop position to the open position, and the time t1 for the diaphragm 4 to open from the stop position to the open position. Since the time t2 required for charging and mirror-up operations is longer than the time required for charging and mirror-up operations, there is a drawback that this becomes a major hindrance to increasing the continuous shooting speed. One possible way to overcome this drawback is to shoot continuously with the aperture closed instead of opening it for each exposure, but in this case, the viewfinder (not shown) It becomes very dark, which makes it difficult to see the subject image during continuous shooting, and makes it difficult to focus, which poses disadvantages in terms of usability.

The present invention eliminates such conventional drawbacks, and provides a viewfinder that enables high-speed continuous shooting without being affected by poor aperture response and is bright enough to cause no problems in use. The purpose is to provide a still camera.

Means for Solving the Problems In order to solve the above problems, the still camera of the present invention includes:
It has a function to perform continuous photography, and is configured to open the aperture by a predetermined amount after one exposure operation is completed during continuous photography, and then close the aperture again for the next photography to perform the photography operation.

Effect With the above configuration, the aperture is not returned to the fully open position for each exposure, so high-speed continuous shooting is possible without being affected by poor aperture response, and the aperture does not remain closed. Since the diaphragm is opened by a predetermined amount, a finder that is bright enough to be used without any problems can be obtained.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing the configuration of a still camera according to an embodiment of the present invention. Components that are the same as those shown in FIG. Omitted. FIG. 2 is a timing diagram showing the mechanical operating states of each part during continuous shooting of the still camera according to the embodiment of the present invention, where (-) indicates the pressing operation of the release button, and 佽) indicates the operation of the aperture. (C) is the operating state of the movable mirror, (d) is the operating state of the leading curtain magnet,
And (θ) indicates the operating state of the trailing curtain magnet.

When the exposure is completed, the opening operation of the aperture 4 is started, and the time t1 required for the aperture 4 to be opened until the viewfinder (not shown) reaches a brightness that does not pose a practical problem.
' is counted by the counting circuit 9, and when the counting of time t1' is completed, an aperture opening operation stop signal is sent to the aperture control circuit 3, and the aperture opening operation is stopped. Therefore, depending on the aperture position during exposure, the aperture is not necessarily opened to the open position. At the same time, the shutter 7 and movable mirror 5 are charged. When charging is completed, the aperture 4 is stopped down and the mirror is raised again, and continuous photographing is performed by the series of operations described above.

As described above, in this embodiment, depending on the position of the aperture at the time of exposure, the aperture is not necessarily returned to the open position for each exposure, and the finder is set at a predetermined position in the trench where the brightness is not a problem for practical use. Since the diaphragm is opened for the time t1', the time required for the diaphragm to open during continuous shooting is shorter than that of a conventional still camera. Moreover, since the aperture 4 is not necessarily returned to the open position,
The time t2' required to narrow down the aperture again is also shorter than in conventional still cameras. Therefore, compared to the conventional example shown in FIG. 3, the time required for the aperture operation during continuous shooting can be shortened by (t1+t2)-(t, '+t2/), and the continuous shooting speed can be increased. What's more, rather than shooting continuously with the aperture stopped down, the aperture is opened until the viewfinder reaches a brightness that is not a problem for practical use, making it easier to see the subject image and adjust focus even during continuous shooting. In fact, it has been experimentally confirmed that the viewfinder can provide sufficient brightness for practical use by opening the aperture by a certain amount, without having to fully open the aperture.

In the above embodiment, the aperture is opened for a predetermined period of time after the exposure is completed during continuous shooting.
Instead of controlling the amount of aperture opening by time, we calculate the number of steps the aperture needs to open so that the viewfinder has a brightness that does not pose a practical problem, and we install a circuit that counts the number of steps the aperture is open. A similar effect can be obtained by controlling the aperture by counting the amount of opening. In particular, with an aperture mechanism that uses a step motor, etc., the time required per step is almost constant, so if you decide the number of steps to open the aperture,
The time required for the aperture operation during continuous shooting is almost constant regardless of the aperture value, and the continuous shooting speed does not slow down depending on the aperture value.

Effects of the Invention As described above, in the present invention, the aperture is not necessarily returned to the fully open position after each exposure during continuous shooting, but the aperture is opened for a predetermined time or a predetermined number of steps after the exposure is completed. This enables high-speed continuous shooting without being affected by poor aperture response. What's more, instead of shooting continuously with the aperture closed, the aperture is opened after each exposure to a point where the brightness of the viewfinder is no longer a practical problem. It has the excellent feature of being easy to use.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the main parts of a still camera according to an embodiment of the present invention, Fig. 2 is a timing diagram showing the mechanical operating state of each part during continuous shooting, and Fig. 3 is the configuration of a conventional still camera. FIG. 4 is a timing diagram showing the mechanical operating state of each part of the conventional still camera during continuous shooting. 2... System control circuit, 3... Aperture control circuit, 4... Aperture, 5... Movable mirror, 6... Shutter drive circuit, 7...
shutter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure ^ He he he he he ku
--〇-5 Figure 3

Claims (1)

[Claims] A photographing means that performs continuous photography, and after one exposure operation is completed during continuous photography, the aperture is opened for a predetermined time or a predetermined number of stops in order for the finder to have a predetermined brightness, and the aperture is opened for the predetermined time or the predetermined number of stops. 1. A still camera comprising: aperture control means for narrowing down the aperture to a predetermined aperture value again after the operation is completed.