JPH0223780A - Still video camera - Google Patents

Abstract

PURPOSE:To attain proper exposure even if a lens other than an interchangeable lens is mounted by discriminating the sort of a mounted lens, and changing timing to start the travel of a shutter in conformity to the result of discrimination. CONSTITUTION:When the mounted lens is for still video use (exclusive lens), since a SV lens signal is inputted to one input terminal of an AND gate 9, a stopping-down finish signal is transmitted as a signal to permit the start of the travel of the shutter to a shutter control circuit 3 through the gate 9 and an OR gate 8. Therefore, the shutter 4 operates in conformity to a shutter second time value from a second time set circuit 2. On the other hand, when the mounted lens is the interchangeable lens, since the SV signal is not inputted to the gate 9, the stopping-down finish signal is transmitted to the control circuit 3 through the gate 8 after prescribed time elapses through a timer 7. Accordingly, the shutter comes to operate in conformity to the shutter second time value from the set circuit 2 later than the case of the mounting of the interchangeable lens by the lapse of prescribed time.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a still video camera with interchangeable lenses, and more particularly to a still video camera to which both a film camera (silver halide camera) lens and a still video camera lens can be attached. Regarding.

(Background of the invention) A step motor is built into the interchangeable lens of a camera.
Lenses that directly drive the aperture have been put into practical use, but even after the step motor has stopped the aperture to a predetermined aperture value, the aperture still bounces for a while, so it is necessary to wait until the bounce has stopped before taking a picture. There is.

Therefore, a lens is used in which the time required for the bounce to fall within a certain amount is determined for each lens and each aperture of each lens, and this time is written in advance in a ROM within the lens. The shutter of the camera is configured to operate when a signal indicating that the bounce of the aperture has stopped is transmitted from the lens side to the camera side.

However, a silver halide camera that uses silver halide film and a still video camera that uses an image sensor have different exposure tolerance ranges (latitude), and still video cameras have a very narrow range (for example, ±3 for silver halide cameras). However, for a still video camera, the exposure range is ±05), so for example, even if the amount of bounce with a lens for a silver halide camera falls within the allowable range of the film, it will still fall within the allowable exposure range for a still video camera. is often not included.

Therefore, if a silver halide camera lens is attached to a still video camera and the shutter is activated immediately upon receiving an aperture drive completion signal from the lens when shooting, uneven exposure will occur within the screen due to aperture bounce. Cheap.

This phenomenon becomes particularly noticeable when using a focal plane shutter with a high-speed slit time.

FIG. 2 is a diagram showing the above-mentioned bounding state of the diaphragm.
After the release, the aperture is driven to a predetermined position, but as shown in the figure, a bounce remains after overrun.

A is an allowable bounce amount, and the value of A is different between a silver halide camera and a still video camera.

(Object of the Invention) An object of the present invention is to solve the above-mentioned problems and provide a still video camera that can provide proper exposure even when a lens other than the dedicated lens is attached. It is.

(Features of the Invention) In order to achieve the above object, the present invention provides a discriminating means for discriminating whether the attached lens is a dedicated lens or a film camera lens, and a shutter movement according to the result of the discriminating means. A travel start time determining means is provided for determining whether the start time is a first timing or a second timing later than the first timing, and the camera is equipped with a dedicated lens. The present invention is characterized in that it automatically discriminates whether the lens is attached or a film camera lens is attached, and the release time lag is changed according to this result.

(Embodiment of the Invention) FIG. 1 is a block diagram showing an embodiment of the present invention, in which the left side from the contact portion shows the schematic structure of an interchangeable lens, and the right side shows the schematic structure of a still video camera body.

In the above configuration, when the first stroke of the release button (not shown) is made, the first stroke signal swl is transmitted from the release control circuit 1 to the CPU II on the interchangeable lens side. Then, the CPU II transmits the lens's maximum aperture value Avo and the bending correction value Avc based on the lens's maximum aperture value to the camera, based on information previously written in the ROM 12.

The arithmetic circuit 6 within the camera body that receives and receives information on the open aperture value Avo and the bending correction value Avc further receives the shutter speed value from the second setting circuit 2 and the subject brightness information from the photometry circuit 5. The aperture value Av is calculated and output to the interchangeable lens side.

Next, when the second stroke of the release button is made,
A second stroke signal (release signal) sw2 is transmitted from the release control circuit 1 to the CPU II on the interchangeable lens side. Then, the CPU II adjusts the aperture 1 via the aperture drive circuit 13 according to the aperture value Av sent from the camera body.
Drive 4. Thereafter, the diaphragm 14 is stopped down to a predetermined position, and when the time period for which the bounce of the diaphragm 14 is to be stopped has elapsed, a diaphragm completion signal is transmitted to the camera body side.

At this time, if the attached lens is a still video camera lens (dedicated lens), the S ■ lens signal is input to one input terminal of the AND gate 9, and therefore a stop-down completion signal is generated. Therefore, the signal is sent to the shutter control circuit 3 via the AND gate 9 and the OR gate 8.
Since the shutter 4 is transmitted as a signal to permit the shutter 4 to start running, the shutter 4 operates in accordance with the shutter time value from the time setting circuit 2.

On the other hand, if the lens attached to the camera is an interchangeable lens for a silver halide camera, the SV lens signal is not input to the AND gate 9, so even if the stop-down completion signal is generated, the SV lens signal is not input to the AND gate 9. The signal is never output. Instead, via the timer 7, after a predetermined time has elapsed, the shutter control circuit 3
It is transmitted to Therefore, the shutter 4 will operate according to the shutter time value from the time setting circuit 2 after a predetermined period of time has elapsed compared to when a dedicated lens is attached.

According to this embodiment, when a lens for a silver halide camera with a wide exposure tolerance is attached to a still video camera with a narrow exposure tolerance, the shutter 4 is activated after a predetermined delay. In other words, if the lens is for a still video camera, the shutter 4 will be activated immediately when a signal indicating that the aperture 14 has stabilized (stopping completion signal) is received, but if a lens for a silver halide camera is attached. Even if a signal indicating that the aperture 14 is stable is received, the shutter 4 is not activated immediately, but is activated after a certain period of time has elapsed, so that the aperture 14 does not appear on the screen.
This eliminates the occurrence of uneven exposure due to bounce of the image.

(Correspondence between the invention and the embodiment) In this embodiment, the AND gate 9 corresponds to the determining means of the present invention, and the OR gate 8 corresponds to the travel start time determining means. Also, the output timing of the AND gate 9 is the first
The output timing of the timer 7 corresponds to the second timing.

(Effects of the Invention) As described above, according to the present invention, there is provided a discriminating means for discriminating whether the attached lens is a dedicated lens or a film camera lens, and a shutter movement according to the result of the discriminating means. A travel start time determining means is provided for determining whether the start time is a first timing or a second timing later than the first timing, and the camera is equipped with a dedicated lens. It automatically determines whether a camera lens is attached or a film camera lens is attached, and the release time lag is changed according to this result, so if a lens other than the dedicated lens is attached. However, it is possible to provide appropriate exposure even when the exposure is low.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a bound state of the aperture when the aperture is narrowed down to a predetermined position. 3...Shutter control circuit, 4...Shutter, 7...Timer, 8...OR gate, 9...And gate, 11...・・・・・・C
PU, 13... Aperture drive circuit, 14...
・Aperture.

Claims (1)

[Claims] (1) In a still video camera that can be equipped with a lens for a film camera in addition to a lens dedicated to a still video camera, a determination means for determining whether the attached lens is a dedicated lens or a lens for a film camera; Depending on the result of the determination means, the timing for starting the shutter movement is determined by the first
A still video camera characterized in that the still video camera is provided with a running start timing determining means for determining whether to use a timing of 1 or a second timing later than the first timing.