JPH01320876A - AE device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a (TTL) AE device that determines exposure using an image sensor in a still video (SV) camera.

[Conventional technology]

Conventionally, in the Sv camera, the AE device has been configured with a separate optical system using a light receiving element different from the image sensor.

[Problem to be solved by the invention]

Therefore, in the conventional example, it is necessary to provide a light receiving element and an optical system for AE in addition to an image pickup element serving as a light receiving element and a photographing lens. Furthermore, there are variations in sensitivity between the image sensor and the light receiving element for AE, which causes errors during photometry and exposure, and adjustments must be made for each camera.

In addition, image sensors generally have a drawback in that they have a narrow latitude for use as light-receiving elements for photometry.

Therefore, the purpose of the present invention is to solve the above-mentioned problems.
The objective is to provide an E-device.

[Means for Solving the Problems] The present invention is characterized by providing means for reading out signals from the image sensor by changing the exposure time for each line or element of the image sensor.

[Function] According to the present invention, since the image sensor also performs photometry,
The AE light receiving element and optical system can be omitted. Also,
Since light metering is performed using the image sensor, there is no exposure error between metering and shooting.

Then, by using an image sensor capable of reading out any element as the image sensor and reading out any element at any exposure time, a wide photometry range is realized despite the narrow latitude.

[First Act & Example] FIG. 1 shows the configuration of an Sv camera according to an embodiment of the present invention.

1 is an image sensor (IM8 to E5) that has an electronic shutter that can read out any line at any time.
ENSOR). Reference numeral 2 denotes an AE device that processes signals read from the image sensor to obtain data for determining the aperture, shutter speed, amount of flash light, etc., and outputs the data to the CPt 13. CPII3 controls the entire tree SV camera. Note that the shutter uses an electronic shutter, so there is no mechanical shutter. SWI is a switch for performing preparatory operations for shooting such as AE, and SW2
is a switch for taking pictures.

5 is a lens, 6 is an aperture, 8 is a driver for driving the lens and the aperture, 11 is a process circuit that generates brightness and color difference signals from the signal output from the image sensor 1, and 12 is a process circuit that generates brightness and color difference signals output from the process circuit 11. A recording circuit performs processing such as modulation on the color difference signal, and 4 is a video floppy which is a magnetic recording medium.

14 is a motor for rotating the video floppy 4;
5 is a recording head for recording signals on the video floppy 4; 13 is a recording head 15. A driver for driving the motor 14, 7 a strobe, 9 an LCD for displaying the status, and 10 an I10 circuit.

Next, the operation will be explained with reference to FIG.

First, when the switch SWI is turned on (Sl), 1.2, 3. The exposure time of each line of ... is 2n-1・t (ms) (where n=1.2
,3. . . , t is an arbitrary value (the shortest time of the electronic shutter of the image sensor), exposure is performed, and a signal is output to the AE device 2. The AE device 2 calculates a value of n that is close to the appropriate exposure value at each of the m locations and outputs it to the CPU 3. CPIJ3 narrows down the results from these data.

Find out the shutter speed, whether to use a strobe, etc. (S
l). Then, when switch SW2 is turned on, (S3)
In S4, CI'U determines whether the photo is taken with a strobe, and if the strobe is not as dark as necessary, the aperture is set to the calculated value, and the shutter speed is adjusted by 178 EV ±I around the calculated shutter speed.
EV, a line that changes the speed of the electronic shutter,
Exposure is performed at m locations and the shutter speed is determined (S
5).

If a strobe is required (S6), the CPU 3 determines the aperture, shutter speed, and GNO (light emission amount) of the strobe using the subject distance data (S6).

Next, in S7, set the aperture to the value obtained, and in S8, move the electronic shutter to perform exposure, and use the video floppy 4 (VIDEOFLOPPY) as a recording medium.
to be recorded.

[Second Embodiment] In the above embodiment, the maximum speed of the electronic shutter is
= about 10 and the open aperture is about AV = 2, it is only possible to measure up to EV = 12, so T
If it is already over at V=10, immediately AV=8
After narrowing it down to a certain degree, it is carried out as in the above embodiment.

Furthermore, the minimum speed of the electronic shutter during photometry is set to about TV=5 to reduce the shutter time lag as much as possible. Even if TV=5 and AV=2, if the camera is under the camera, it will be shot with a strobe light, and depending on the subject distance, the TV,
Determine AV.

(Third Embodiment) In the photometry during the flash AE (S2) of the first embodiment, it is sufficient to measure the light with an error of ±IEV or less with respect to the appropriate exposure value. For color, for distance measurement,
It is used for strobe light control, etc., and at least ±
A colorimetric sensor that can measure light with an error on the order of IEV,
Light measurement is performed using at least one of a distance measurement sensor, a strobe light control sensor, etc., and a pre-AE (S2) operation is performed.

(Effects of the Invention) As explained above, since exposure is performed by changing the exposure time for each line, it is possible to perform photometry in a wide EV range even with an image sensor having a narrow latitude, and there is no need for a light receiving element dedicated to photometry.

Since photometry is performed using the image sensor, there is no need to adjust the sensitivity of the image sensor and the photometric photoreceptor for variations in the sensitivity of each product.

Therefore, a low-cost, highly accurate TTL direct photometry system can be constructed.

In addition, since exposure is performed using different lines, it may be inconvenient depending on the subject, but it is possible to determine the exposure quickly and in a shorter time than using the same line and metering by changing the exposure time, and there is no shutter time lag. less.

Additionally, because it is a TTL system, it can also be used with zoom lenses, which are the mainstream of recent years.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, Figure 2 is a schematic diagram of the image sensor; FIG. 3 is a flowchart of this embodiment.

Claims (1)

[Claims] An AE device comprising means for reading signals from an image sensor by changing exposure time for each line or element of the image sensor.