JP2964531B2 - Camera with electronic viewfinder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide camera, and more particularly to a camera with an electronic finder that displays a subject image on the electronic finder.

[Conventional technology]

In general, an electronic finder is used for a video camera, but an electronic finder employing an electronic finder for a silver halide camera has been proposed (Japanese Patent Laid-Open No. 63-284528).

This camera with an electronic viewfinder has a function of storing an image signal sent from the CCD at the time of shutter release in a memory, and then displaying a still image at the time of shooting on a liquid crystal display based on the image signal stored in the memory. ing.

[Problems to be solved by the invention]

However, in the above-described conventional camera with an electronic viewfinder, the image signal sent from the CCD is simply stored in the memory in synchronization with the shutter release, so that the image is displayed on the liquid crystal display based on the image signal stored in the memory. The still image cannot be said to accurately represent the image of the subject captured on the film.

In other words, camera shake, strobe arrival detection, and the like cannot be accurately determined for the still image.

The present invention has been made in view of such circumstances, and an image closer to a subject image captured on a film can be immediately displayed on an electronic viewfinder after being photographed. It is an object of the present invention to provide a camera with an electronic finder capable of detecting the above.

[Means for solving the problem]

In order to achieve the above object, the present invention focuses light from a subject on a light receiving unit of an imaging device, and displays a moving image indicating a subject image on an electronic finder based on image signals sequentially read from the imaging device. Means for detecting a shutter speed of the shutter and a release signal synchronized with a shutter release, and an image signal for one screen in a camera with an electronic finder that exposes a silver halide film with light from a subject by controlling opening and closing of a shutter. Means for storing charge in the imaging device in synchronization with the detected release signal at the time of the shutter release, and means for matching the charge storage time in the imaging device with the detected shutter speed; After a lapse of the shutter speed, the image is stored in the imaging device. Means for reading an image signal corresponding to the received signal charge from the imaging device, storing the image signal in the storage means, reading an image signal from the storage means, and displaying a still image on the electronic finder based on the image signal. And means for causing it to be provided.

[Action]

According to the present invention, an image signal corresponding to the same subject light (subject light having exactly the same time and timing) as the subject light that actually exposed the film is extracted from the imaging device. The time and timing can be detected from the speed and shutter release determined at the time of shooting. Then, the image signal extracted as described above is stored in the storage means, and after photographing, read out as appropriate from the storage means and displayed as a still image on the electronic finder.

[Embodiment] Hereinafter, a preferred embodiment of a camera with an electronic finder according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a main block diagram showing an embodiment of a camera with an electronic finder according to the present invention. This camera is a silver halide camera that captures an image of a subject on a silver halide film via a photographic lens (not shown).

In the same figure, light from the subject is
An image is formed on the light receiving unit of the solid-state imaging device (CCD) 12 via the.

Each of the two-dimensionally arranged photoelectric conversion elements of the CCD 12 generates a signal corresponding to the intensity of light incident on that part, and this signal charge is transmitted to an LCD from a system controller 14 described later.
It is stored in each photoelectric conversion element for an appropriate period based on the drive signal. The signal charges thus accumulated are sequentially read out and added to the signal processing circuit 16.

The signal processing circuit 16 sequentially converts signal charges sequentially input from the CCD into image signals for liquid crystal display based on a synchronization signal from the system controller 14, and converts the image signals into a changeover switch 18.
And output it to the memory 22 via the A / D converter 20.

The memory 22 stores an image signal for one screen and outputs the stored image signal.
A digital image signal input from the A / D converter 20 is stored for one screen based on a write command added at an appropriate timing from the CPU. The digital image signal stored in the memory 22 is sequentially and repeatedly read out and output to the terminal 18B of the changeover switch 18 via the A / D converter 24.

The changeover switch 18 switches and connects the movable contact piece 18C to the terminal A or the terminal B based on a switch changeover signal from the system controller 14, and outputs an image signal input to the terminal A or the terminal B to a liquid crystal display (LCD) 26. I do.

The LCD 26 is provided as a liquid crystal finder, for example, on the back of the camera, is driven by an LCD drive signal applied from the system controller 14, and displays a finder image on the liquid crystal display based on an image signal input via the changeover switch 18.

Next, the operation of the system controller 14 will be described.

The system controller 14 measures the subject brightness
A signal indicating a shutter speed set based on the output of an AE sensor (not shown) and a release signal synchronized with the shutter release are added.

When the release signal is not input, the system controller 14 connects the movable contact 18C of the changeover switch 18 to the terminal A.
And a CCD drive signal is output so that the charge accumulation time in the CCD 12 is one vertical period (one field period).

Therefore, the signal charges accumulated in the photoelectric conversion elements of the CCD 12 during one field period are sequentially read out during the next one field period, converted into an image signal for liquid crystal display by the signal processing circuit 16, and then changed over by the changeover switch 18. Via the LCD 26.

Thus, the LCD 26 displays a finder image of a moving image.

On the other hand, when the release signal is input to the system controller 14, the system controller 14 matches the charge accumulation time in the CCD 12 with the shutter speed based on the signal indicating the shutter speed input at that time, and starts the charge accumulation. CCD1 to synchronize with the release signal
Control two.

That is, the system controller 14 causes the vertical transfer CCD to read out unnecessary charges accumulated in each photoelectric conversion element of the CCD 12 in synchronization with the release signal, and starts accumulating new signal charges. Unnecessary charges read out at the same time are swept out from the drain, and after the lapse of the shutter speed, the signal charges accumulated within the time are read out by the vertical transfer CCD.

The signal charges read out to the vertical transfer CCD are sequentially transferred in the direction of the horizontal transfer CCD every one horizontal period (1H), and transferred to the last stage of the vertical transfer CCD as in the case of normal reading. The transferred signal charges are sequentially transferred to the horizontal transfer stage every horizontal retrace period, and are sequentially taken out in the next horizontal scanning time.

The system controller 14 stores the digital image signal output from the CCD 12 as described above and applied to the memory 22 through the signal processing circuit 16 and the A / D converter 20.
22 and the movable contact piece 18 of the changeover switch 18
By switching C to the terminal 18B, the image signal read from the memory 2 is output to the LCD 26 via the D / A converter 24 and the switch 18.

As a result, the LCD 26 displays a still image having the same information as the subject image projected on the film when the shutter is released.

When switching from the still image to the moving image, the switch 18 may be switched when the shutter release button is fully pressed, for example. The switch 18 may be switched manually. . In this embodiment, the finder lens 10 is used. However, a configuration in which light passing through the photographing lens is separated by a beam splitter and guided to the CCD 12 may be used.

〔The invention's effect〕

As described above, according to the camera with the electronic finder according to the present invention, a still image captured at the same shutter speed and at the same timing as the subject image to be photographed on the film can be displayed on the electronic finder. It is possible to detect whether the strobe has not arrived or not, and to judge whether or not the photographing has failed. When the photographing fails, the photographing can be performed again, so that the photographer can be given a sense of security.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing an embodiment of a camera with an electronic finder according to the present invention. 10: finder lens, 12: solid-state imaging device (CCD), 14: system controller, 16: signal processing circuit, 18: switch, 22: memory, 26: liquid crystal display (LCD).

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-145641 (JP, A) JP-A-2-101441 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) G03B 17/18-17/20 G03B 15/00

Claims (1)

(57) [Claims] An image of light from a subject is formed on a light receiving portion of an image pickup device, and a moving image indicating a subject image is displayed on an electronic finder based on an image signal sequentially read from the image pickup device, and a shutter is opened and closed. A camera with an electronic viewfinder that exposes the silver halide film with light from a subject, wherein: a means for detecting a shutter speed of the shutter and a release signal synchronized with a shutter release; and a storage means for storing an image signal for one screen. Means for starting charge accumulation in the imaging device in synchronization with the detected release signal at the time of the shutter release, and for making the charge accumulation time in the imaging device coincide with the detected shutter speed; Later, the signal charge corresponding to the signal charge stored in the imaging device is Means for reading an image signal from the imaging device and storing the image signal in the storage means, and means for reading an image signal from the storage means and displaying a still image on the electronic finder based on the image signal. A camera with an electronic viewfinder, comprising: