JP2003244537A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To widen an AE link range and to prevent occurrence of smear. <P>SOLUTION: If electronic zoom magnification value and recording pixel number are selected, a program for AE control corresponding to the selection is selected, combination of the iris aperture and shutter speed of an electronic shutter of a CCD image sensor is decided. The maximum aperture value is set for each program, to obtain necessary resolution power of the camera lens, corresponding to the combination of the zoom multiplication value and to the recording pixel number, and the aperture is set so as not to over the maximum aperture value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera.

[0002]

2. Description of the Related Art A digital camera using a solid-state image sensor, for example, a CCD image sensor is known. Some digital cameras can take still images, some can take moving images, and some can take both. In such a digital camera, the amount of light incident on the solid-state image sensor is adjusted by the charge accumulation time of the solid-state image sensor, the shutter speed of the electronic shutter, and the diaphragm device arranged on the shooting optical path, to obtain proper exposure. I am trying.

[0003]

By the way, if the aperture value that can be set by the aperture device is increased (the aperture diameter is decreased), the AE interlocking range can be expanded, but if the aperture value is increased too much, Diffraction of light is caused by the diaphragm, and the performance of the taking lens, especially the resolution is degraded. When the resolving power of the photographing lens is reduced in this way, there is a problem that even if a solid-state image sensor having a high resolving power is used, only an image having a lower resolving power is obtained.

Further, when a still image is taken, it is possible to prevent strong light from entering outside the period of charge accumulation by using a mechanical shutter device in combination, and smear is generated without narrowing the aperture. Can be suppressed. However, when shooting a moving image, it is difficult to use a mechanical shutter device together, so unless the aperture is narrowed down, strong light enters the solid-state image sensor outside the period of charge accumulation, causing smear. There was a problem that it became easier to do.

The present invention is intended to solve the above-mentioned problems, and it ensures AE while ensuring the necessary resolving power of the taking lens.
An object of the present invention is to provide a digital camera capable of expanding the interlocking range and reducing the occurrence of smear when shooting a moving image.

[0006]

In order to achieve the above object, in the invention according to claim 1, the maximum aperture that can be used is adjusted in accordance with the resolving power of the photographing lens required according to the number of recording pixels to be converted. It sets the value.

According to the second aspect of the invention, the maximum usable aperture value is set in accordance with the resolving power of the taking lens required according to the zoom magnification of the electronic zoom.

According to the third aspect of the present invention, the maximum usable aperture value is set in accordance with the resolving power of the photographing lens required according to the combination of the zoom magnification of the electronic zoom and the number of recording pixels to be converted. Is.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the rear side of the external appearance of a digital camera. On the front surface of the camera body 2, the taking lens 3
A lens barrel 4 holding (see FIG. 2) is arranged. Also,
An operation unit 5, a zoom operation unit 6, and an LCD 7 are provided on the back surface. Further, a release button 9 is arranged on the upper surface, and a memory slot 11 into which a memory card 10 is inserted is provided on the side surface.

The taking lens 3 held by the lens barrel 4 is of a single focus type. A CCD image sensor 13 (see FIG. 2) is arranged in the back of the taking lens 3, and the subject image is taken by the CCD image sensor 13. As the CCD image sensor 13, one that outputs an image pickup signal for 1600 × 1200 pixels for one screen is used.

The operating section 5 is operated to
Power on / off, switching between shooting mode and playback mode, switching between still image mode and movie mode under shooting mode, switching of pixel mode, selection of image to be played back under playback mode, deletion of image data, etc. be able to.

In the still image mode, each time the release button 9 is pressed, one image of a still image is taken by the CCD image sensor 13 and the obtained image data is recorded in the memory card 10. In the moving image mode, pressing the release button 9 starts the shooting of a moving image by the CCD image sensor 13, and when the release button 9 is pressed next, the shooting of the moving image is stopped, and the obtained moving image data is stored. It is recorded in the memory card 10.

By switching the pixel mode, the number of pixels for one screen to be recorded on the memory card 10 can be selected. 1600 x 1200 in still image mode
1600 pixel mode for pixels, 1 for 1280 x 960 pixels
Either the 280-pixel mode or the 640 × 480-pixel 640-pixel mode can be selected. Also, in video mode,
The 640 pixel mode is set.

By operating the zoom operating section 6,
The zoom magnification by electronic zoom is changed. There are three types of zoom magnifications: 1x, 1.25x, and 2.5x. The zoom operation unit 6 includes a telephoto side button 6a and a wide-angle side button 6b. By pressing the telephoto side button 6a, the zoom magnification is sequentially increased, and by pressing the wide-angle side button 6b, the zoom magnification is sequentially decreased. In the initial state immediately after the power is turned on, the zoom magnification is set to 1.

In the 1600 pixel mode, the zoom magnification is fixed at 1. Also, in the 1280 pixel mode, the zoom magnification can be selected from 1 × or 1.25 ×, and in the 640 pixel mode, the zoom magnification can be selected from 1 ×, 1.25 × or 2.5 ×. Can be selected.

The LCD 7 constitutes a so-called electronic viewfinder for displaying a subject image photographed through the photographing lens 3 in real time, and is used for image reproduction and the like.

A photographed subject image is recorded as image data in a memory card 10 as a storage medium in which an image is recorded. In this example, the memory card 10 that can be inserted into and removed from the digital camera is used as a storage medium, but various types of storage media can be used.
The image data may be recorded in a memory built in the digital camera.

FIG. 2 shows a schematic structure of the digital camera. The system controller 14 controls each unit of the digital camera. As described above, the CCD image sensor 13 is arranged behind the taking lens 3. The taking lens 3 is driven by an autofocus mechanism (not shown) so that a subject image is formed on the light receiving surface of the CCD image sensor 13.

The taking lens 3 and the CCD image sensor 13
A diaphragm plate 15 that constitutes a diaphragm device and a shutter blade 16 are disposed between and. The diaphragm plate 15 controls the intensity of light incident on the CCD image sensor 13. The diaphragm plate 15 can be controlled, for example, in a range of an aperture value of F2.8 to F16. However, as will be described later, the maximum aperture value (minimum aperture opening diameter) depends on the combination of the pixel mode and the zoom magnification. It is prescribed.

The shutter blade 16 is for preventing the occurrence of smear at the time of shooting a still image, and opens and closes in synchronization with the operation of the electronic shutter of the CCD image sensor 13 at the time of shooting a still image. Note that the shutter blades 16 are open when shooting a moving image.

The CCD image sensor 13 has a large number of light receiving elements arranged in a matrix on its light receiving surface. In this CCD image sensor 13, the charge accumulation time, that is, the shutter speed of the electronic shutter is controlled by the CCD driver 17. When the electronic shutter is open, the CCD image sensor 13 photoelectrically converts the light from the taking lens 3 and accumulates it as electric charge, and sequentially transfers the accumulated electric charge to output an image pickup signal. The charge accumulation amount (exposure amount) of each light receiving element of the CCD image sensor 13 is adjusted by the diaphragm plate 16 and the shutter speed of the electronic shutter.

At the time of taking a still image, the shutter blade 16 is once closed, and the CCD image sensor 13 is closed in the meantime.
Unnecessary electric charges stored in are discharged. Then, almost simultaneously with the opening of the shutter blade 16, the electronic shutter of the CCD image sensor 13 is opened, photoelectric conversion is performed, and charges are accumulated. Immediately after the electronic shutter is closed, the shutter blade 16 is closed. While the shutter blade 16 is closed, charges are transferred and an image pickup signal for one screen is output.

At the time of photographing a moving image, the exposure amount of the CCD image sensor 13 is adjusted by the shutter speed of the electronic shutter of the CCD image sensor 13 and the diaphragm plate 16 with the shutter blades 16 opened.

The image pickup signal from the CCD image sensor 13 is sent to the A / D converter 19 through the amplifier 18 and fed back to the AE control circuit 20. A
The E control circuit 20 determines the subject brightness by monitoring the signal level of the image pickup signal output from the amplifier 18. The AE control circuit 20 controls the aperture value of the aperture plate 15 so that an appropriate exposure amount can be obtained for the determined subject brightness, and the CC driver via the CCD driver 17
The shutter speed of the electronic shutter of the D image sensor 13 is controlled.

The AE control circuit 20 is provided with three types of programs for exposure control, examples of which are shown in FIGS. 3 is a program for high resolution with a maximum aperture value of "F8", FIG. 4 is a program for medium resolution with a maximum aperture value of "F11", and FIG. 5 is a program for low resolution with a maximum aperture value of "F16". Is. In both programs, the diaphragm plate 16 is prevented from being narrowed down beyond the maximum diaphragm value set therein.

The AE control circuit 20 determines the shutter speed of the electronic shutter and the aperture value of the aperture plate 16 with respect to the brightness of the subject according to one program based on an instruction from the system controller 14.

The A / D converter 19 samples and digitally converts the input image pickup signal and outputs image data. The A / D converter 19 converts the image pickup signal for one screen into image data for 1600 × 1200 pixels. The image data is sent to the image data processing circuit 21.

The image data processing circuit 21 performs various signal processing such as gamma correction and white balance adjustment on the input image data. Further, the image data processing circuit 21 performs image processing according to the selected pixel mode, that is, the number of recorded pixels and the zoom magnification of the electronic zoom. This image processing includes trimming processing and pixel number conversion processing.

In the trimming processing, a screen (photographing range) of 1600 × 1200 pixels photographed by the CCD image sensor 13 is used as a reference, and a range corresponding to the zoom magnification is cut out from this screen to obtain a photographing range corresponding to the zoom magnification. Create a new screen. In the pixel number conversion process, the number of pixels forming the screen is reduced while keeping the same screen range (shooting range). Since the trimming process is a process of cutting out a part of the screen, the resolving power of the necessary photographing lens does not decrease, but in the pixel number conversion process,
For example, the number of pixels is reduced so as to generate “N−1” pixels from N (> 1) pixels, and the necessary resolution of the taking lens is reduced in order to convert to a desired number of pixels.

1600 pixel mode (zoom magnification is 1)
When, the trimming process and the pixel number reduction image process are not performed. Therefore, image data for 1600 × 1200 pixels is output from the image data processing circuit 21.

When the zoom magnification is 1 in the 1280 pixel mode, only the pixel number conversion processing is performed and 1600
1280 × 9 based on the image data of × 1200 pixels
Image data of 60 pixels is generated. Further, when the zoom magnification is 1.25 times in the 1280 pixel mode, only the trimming process is performed, and the range of 1280 × 960 pixels is cut out from the range of 1600 × 1200 pixels.

When the zoom magnification is 1 in the 640 pixel mode, only the pixel number conversion processing is performed and 1600 ×
Image data for 640 × 480 pixels is generated from the image data for 1200 pixels. In addition, when the zoom magnification is 1.25 times under the 640 pixel mode, 12 trimmed out from the range of 1600 × 1200 pixels.
The image data for 80 × 960 pixels is converted into the image data for 640 × 480 pixels by the pixel number conversion process. Furthermore, the zoom factor is 2.5 under the 640 pixel mode.
When doubled, only the trimming process is performed and 160
The range of 640 × 480 pixels is cut out from 0 × 1200 pixels.

Image data from the image data processing circuit 21 is input to the LCD driver 22. The LCD driver 22 drives the LCD 7 based on the image data and displays a subject image on the LCD 7. The LCD driver 22 displays a subject image on the LCD 7 with 320 × 240 pixels, for example, by performing a thinning process on the input image data.

The system controller 14 exchanges data with the image data processing circuit 21, the built-in memory 26, and the I / O circuit 27. An operation unit 5, a zoom operation unit 6, a release button 9, and a memory card 10 are connected to the I / O circuit 27. Each operation signal from the operation unit 5, the zoom operation unit 6, and the release button 9 is sent to the system controller 14 via the I / O circuit 27. The system controller 14 controls each part based on these operation signals.

As the built-in memory 26, one that can read and write data at high speed is used. At the time of shooting, the image data to be recorded in the memory card 10 is once written in the internal memory 26. The image data recorded in the built-in memory 26 after the completion of shooting of a still image or a moving image is read by the system controller 14 and sent to the memory card 10 via the I / O circuit 27 to be written therein.

In the reproduction mode, the image data of the selected image is read from the memory card 10 and written in the built-in memory 26, and is sequentially read from the built-in memory 26 to be read by the system controller 25 and the image data processing circuit. It is sent to the LCD driver 22 via 21. As a result, the image stored in the memory card 10 is displayed on the LCD.
It is displayed on 7.

When the operation section 5 is operated to switch the pixel mode, or when the zoom operation section 6 is operated to switch the zoom magnification, an instruction according to the operation content is given via the system controller 14. Is supplied to the image data processing circuit 21. As a result, trimming processing and pixel number conversion processing according to each pixel mode and zoom magnification are performed.

Further, in order to obtain the resolving power determined by the combination of the pixel mode and the zoom magnification with the taking lens 12, the system controller 14 gives an instruction to select a program corresponding to the combination.
Sent to.

FIG. 6 shows the relationship between the number of recorded pixels and zoom magnification, and the maximum aperture value. In this example, the resolving power required when the pixel number conversion process is not performed is obtained when the aperture value is F8, but when the aperture value is narrowed down beyond that, the resolution is lowered due to the diffraction of light by the aperture. You cannot get the resolution. Therefore, when the pixel number conversion processing is not performed, that is, in the 1600 pixel mode, when the zoom magnification is 1.25 times under the 1280 pixel mode, and when the zoom magnification is 2.5 times under the 640 pixel mode, the maximum aperture is reduced. F using the high resolution program whose value is limited to F8
I try not to narrow it down more than 8.

As described above, by performing the pixel number conversion process, the necessary resolving power of the taking lens is lowered. Also,
The higher the ratio of reducing the number of pixels in the pixel number conversion process, the lower the resolving power of the required photographing lens. Therefore, in the case of performing the pixel number conversion process, a reduction in the resolving power of the photographic lens 3 due to the influence of diffraction due to the narrowing of the aperture is allowed as much as the required resolving power of the photographic lens 12 is reduced.

In this example, the maximum aperture value is set to "F11" when the zoom magnification is 1 times under the 1280 pixel mode and when the zoom magnification is 1.25 times under the 640 pixel mode. Is allowed to be narrowed down to F11. Also, in the case of a zoom magnification of 1 under the 640 pixel mode, the maximum aperture value is set to F1.
6 ”, using the low resolution program F16
It is allowed to be narrowed down to.

As described above, depending on the number of recorded pixels and the zoom magnification of the electronic zoom, the resolution range necessary for the taking lens is secured and the brightness range in which an appropriate exposure amount is obtained is widened.

Next, the operation of the above configuration will be described. For example, when shooting a still image, the operation unit 5 is operated to select a shooting mode, then a still image mode, and then a pixel mode. For example, when the 1600 pixel mode is selected, since the zoom magnification of the electronic zoom is 1, the instruction to select the high resolution program is sent to the AE control circuit 20.

After this, the shutter blades 16 are opened and the CCD image sensor 13 continuously shoots a moving image. An image pickup signal obtained by being picked up by the CCD image sensor 13 is sent to an A / D converter 19 and an AE control circuit 20 via an amplifier 18, respectively. Then, based on the signal level of the image pickup signal, the AE
The brightness of the subject is checked by the control circuit 20, and the shutter speed of the electronic shutter of the CCD image sensor 13 and the aperture value F of the aperture plate 15 are adjusted so that an appropriate charge storage amount is obtained. At this time, the AE control circuit 20 controls the shutter speed of the electronic shutter and the aperture value of the diaphragm plate 15 on the basis of the high resolution program, so that the aperture value is high even if the subject brightness is very high. The maximum aperture value is up to F8, and the aperture value is not exceeded.

On the other hand, the image pickup signal sent to the A / D converter 19 is converted into image data by the A / D converter 19. At this time, 1600 × from the image pickup signal for one screen
Image data for 1200 pixels is generated, and the image data is sent to the image data processing circuit 21.

The image data input to the image data processing circuit 21 is subjected to gamma correction, white balance adjustment, trimming processing according to the pixel mode and zoom magnification, and pixel number conversion processing by the image data processing circuit 21. Is sent to the LCD driver 22, but in this case, since the 1600 pixel mode is selected and the zoom magnification is 1, the trimming processing and the pixel number conversion processing are not performed.

In this way, the image data from the image data processing circuit 21 is successively input to the LCD driver 22, so that the subject image being photographed by the CCD image sensor 13 is displayed as a moving image on the LCD 7.

When the 1600 pixel mode is selected as described above, the zoom magnification of the electronic zoom is fixed to 1 ×, but when the 1280 pixel mode is selected, it is 1.25 × in addition to 1 ×. Can be selected as the zoom magnification.

When the operating unit 5 is operated to switch from the 1600 pixel mode to the 1280 pixel mode, the zoom magnification becomes 1.
The system controller 14 gives an instruction for pixel number conversion processing to the image data processing circuit 21 with the number doubled. As a result, the image data of one screen of 1600 × 1200 pixels input to the image data processing circuit 21 is converted into the image data of 1280 × 960 pixels, which is output and sent to the LCD driver 22. Since only the pixel number conversion process is performed, there is no change in the shooting range observed on the LCD 7.

When the 1280 pixel mode and the 1 × zoom magnification are selected, an instruction to select the medium / high resolution program is sent to the AE control circuit 20. As a result, the AE control circuit 20 controls the shutter speed of the electronic shutter and the aperture value of the aperture plate 15 based on the medium resolution program. Therefore, if the subject brightness is very high, the maximum aperture value of the medium resolution program is F11, but the aperture value is not exceeded.

When the telephoto side button 6a of the zoom operation section 6 is pressed after switching to the 1280 pixel mode, the zoom magnification becomes 1.25 times. When the zoom magnification becomes 1.25 times, the image data processing circuit 21 performs only the trimming processing according to the instruction from the system controller 14. As a result, a screen of 1280 × 960 pixels is cut out from a screen of 1600 × 1200 pixels,
The image data is sent to the LCD driver 22. LC
D7 is 1280 × 9 on the CCD image sensor 13.
Since the screen range for 60 pixels is displayed, as a result,
It is possible to observe a subject image in the same shooting range as when the focal length of the taking lens 3 is set to 1.25 times.

When the 1280 pixel mode and the zoom magnification of 1.25 times are selected, the pixel number conversion process is not performed, so that the necessary resolving power of the taking lens 3 is 1.
Since it is no different from the case of 600 pixel mode, 160
As in the 0-pixel mode, the AE control circuit 20 is instructed by the high resolution program, and the shutter speed of the electronic shutter and the aperture value of the aperture plate 15 are controlled based on this instruction. Therefore, the maximum aperture value becomes F8, and the aperture will not be narrowed down beyond that.

When the 640 pixel mode is selected, the zoom operation unit 6 is operated to perform 1 ×, 1.25 ×, and 2.
It becomes possible to select 5 times as the zoom magnification. 640
When 2.5 times is selected as the zoom magnification in the pixel mode, only the trimming process is performed as in the case where 1.25 times is selected in the 1280 pixel mode, and 1600 ×
A screen of 640 × 480 pixels is cut out from the screen of 1200 pixels, and the image data is sent to the LCD driver 22. Since the LCD 7 displays a screen range of 640 × 480 pixels on the CCD image sensor 13, as a result, a subject image in the same shooting range as when the focal length of the shooting lens 3 is increased by 2.5 times. Can be observed. Further, in this case, since the AE control circuit 20 controls the shutter speed of the electronic shutter and the aperture value of the aperture plate 15 based on the high resolution program, the maximum aperture value becomes F8.

When 1.25 times is selected as the zoom magnification in the 640 pixel mode, trimming processing and pixel number conversion processing are performed. First, by a trimming process, a 1280 × 96 screen is displayed from a screen of 1600 × 1200 pixels.
The screen for 0 pixels is cut out. Then 128
The screen of 0x960 pixels is 640 by the pixel number conversion processing.
Converted to × 480 pixels. Then, the image data of 640 × 480 pixels is sent to the LCD driver 22. As a result, the LCD 7 displays a screen range of 1280 × 960 pixels on the CCD image sensor 13, and as a result, the same shooting range as when the focal length of the taking lens 3 is increased by 1.25 times. The subject image can be observed. Further, in this case, since the AE control circuit 20 controls the shutter speed of the electronic shutter and the aperture value of the aperture plate 15 based on the medium resolution program, the maximum aperture value becomes F11.

1 as the zoom magnification under the 640 pixel mode
When double is selected, only the pixel number conversion processing is performed. In this pixel number conversion processing, a screen of 1600 × 1200 pixels is converted to 640 × 480 pixels. Then, the image data of 640 × 480 pixels is displayed on the LCD driver 2
2 is sent to the LCD 7, it is possible to observe on the LCD 7 a subject image in the shooting range shot with the original focal length of the taking lens 3. Further, in this case, since the AE control circuit 20 controls the shutter speed of the electronic shutter and the aperture value of the aperture plate 15 based on the low resolution program, the maximum aperture value becomes F16.

While observing the subject image displayed on the LCD 7 as described above, the zoom is performed under the desired pixel mode.
The frame magnification is selected, the framing is determined, and the release button 9 is pressed.

When the release button 9 is pressed, the shutter blade 16 is once closed and then the shutter blade 1
At the same time when 6 is opened, the electronic shutter of the CCD image sensor 13 is opened, and the light passing through the diaphragm opening formed by the diaphragm plate 15 is photoelectrically converted to accumulate charges. At this time, the combination of the aperture value of the aperture plate 15 and the electronic shutter is based on a program determined by the selected number of recording pixels and the electronic zoom magnification. Therefore, the maximum aperture value is limited by the number of recording pixels and the electronic zoom magnification.

When the electronic shutter of the CCD image sensor 13 is closed, the shutter blades 16 are closed immediately thereafter,
While the shutter blade 16 is closed, the accumulated charges are sequentially transferred and output as an image pickup signal.
Then, this image pickup signal converted into image data is sent to the image data processing circuit 21.

In the image data processing circuit 21, as in the case where the LCD 7 is made to function as an electronic viewfinder, image data subjected to trimming processing and pixel number conversion processing in accordance with the number of recorded pixels and the electronic zoom magnification is processed. It is sent to the built-in memory 26 via the system controller 14 for writing. After this, one screen of image data is read from the built-in memory 26, and the system controller 14 and I / O
The data is transferred to and written in the memory card 10 via the circuit 27.

As a result, if the 1600 pixel mode is selected, the image data of 1600 × 1200 pixels is written and stored in the memory card 10 as one screen. If the 1280 pixel mode is selected,
If the 640 pixel mode is selected for the image data of 80 × 960 pixels, the image data of 640 × 480 pixels is 1
The screen portion is written and saved in the memory card 10. In each case, the subject image is in the shooting range according to the selected zoom magnification.

The image data of each screen recorded as described above has a maximum aperture at the time of photographing so as to ensure a necessary resolving power of the photographing lens which is determined according to the zoom magnification of the electronic zoom and the number of recording pixels. Since the value is limited, it is a high quality image with sufficient resolution.

When shooting a moving image, the operation unit 5 is operated to select the moving image mode. When you select the video mode,
As the pixel mode, the 640 pixel mode is automatically selected.
If you operate the zoom operation button 6 in this movie mode,
With the 640 pixel mode still selected, any one of 1 ×, 1.25 ×, and 2.5 × is selected as the zoom magnification.
Then, as in the case where the 640 pixel mode is selected under the still image mode, trimming processing and pixel number conversion processing are performed according to the selected zoom magnification, and the image data is sent to the LCD driver 22, The subject image being photographed is displayed on the LCD 7.

When the release button 9 is pressed at the timing when a moving image is desired to be recorded, the built-in memory 26 is sequentially passed through the system controller 14 from the image data on which the screen trimming process and the pixel number conversion process have been performed at the time of shooting. Sent to and written in. The writing of the image data is continued until the release button 9 is pressed next time. When the release button 9 is pressed, the built-in memory 26
When the writing to the memory card is completed, the data is transferred from the built-in memory 26 to the memory card 10 and written. As a result, the moving image is recorded in the memory card 10 at the selected zoom magnification, and each screen forming the moving image has 640 × 480 pixels.

Even in the case of shooting a moving image in the moving image mode in this way, the AE control circuit 20 has an aperture according to a program corresponding to the combination of the number of recording pixels and the zoom magnification of the electronic zoom, as in the still image mode. The exposure amount of the CCD image sensor 13 is controlled by the combination of the value and the shutter speed of the electronic shutter. In this video mode, 6
Since it is fixed to the 40-pixel mode, the program is switched according to the zoom magnification and the maximum aperture value is switched.

In the moving image mode, since the shutter blades 16 are open, smear is likely to occur,
In this digital camera, since it is possible to narrow down the image as much as possible, it is possible to suppress the occurrence of smear, and it is possible to secure the necessary resolution, so that the image quality is not deteriorated.

In the above embodiment, the case where the number of recording pixels and the electronic zoom are used together has been described. However, when the number of recording pixels is switched while keeping the zoom magnification constant, and when the zoom magnification is switched while keeping the number of recording pixels constant. The present invention can also be used for Further, although the example in which the image is captured by the CCD image sensor has been described, other image pickup devices may be used.

[0067]

As described above, according to the present invention, the maximum usable aperture value is set in accordance with the zoom magnification of the electronic zoom, the number of recording pixels to be converted, or a combination thereof. Since the resolving power of the photographic lens is obtained, it is possible to widen the AE interlocking range without deteriorating the image quality, and it is possible to reduce the occurrence of smear during moving image shooting.

[Brief description of drawings]

FIG. 1 is a perspective view showing the external appearance of a digital camera embodying the present invention.

FIG. 2 is a block diagram showing a configuration of a digital camera.

FIG. 3 shows a program for high resolution with a maximum aperture value of F8.

FIG. 4 shows a medium resolution program with a maximum aperture value of F11.

FIG. 5 shows a low resolution program with a maximum aperture value of F16.

FIG. 6 shows the relationship between the maximum aperture value according to the combination of the zoom magnification of the electronic zoom and the number of recording pixels.

[Explanation of symbols]

3 shooting lens 5 Operation part 6 Zoom operation section 10 memory card 13 CCD image sensor 20 AE control circuit 21 Image data processing circuit

Claims (3)

[Claims] 1. A digital camera having a conversion means for converting the number of pixels of a screen shot to a designated number of recording pixels, in accordance with the resolving power of a photographing lens required according to the number of recording pixels to be converted. , A digital camera characterized by setting the maximum aperture value that can be used. 2. A digital camera having an electronic zoom function, wherein the maximum usable aperture value is set according to the resolving power of the taking lens required according to the zoom magnification of the electronic zoom. Digital camera. 3. A digital camera provided with an electronic zoom function and a conversion means for converting the number of pixels of a screen shot into a designated number of recording pixels, wherein a zoom magnification of the electronic zoom and a number of recording pixels to be converted are provided. A digital camera characterized by setting the maximum usable aperture value according to the resolving power of the photographic lens required depending on the combination of.