JPH05249534A - Automatic bracketing device for camera - Google Patents

Abstract

PURPOSE:To facilitate the automatic set of the respective parameters of the automatic bracketing device of a camera and to facilitate efficient and precise automatic bracketing photographing. CONSTITUTION:The automatic bracketing device of the camera, which successively executes the photographing of plural frames by changing an exposure value by prescribed amount one time, is provided with multi-photometry means 1, 11 and 13 which execute photometry by dividing an object into plural areas and generate plural photoelectric outputs corresponding to the brightness of the respective areas and a processing output required for giving precise exposure by processing the photoelectric output, judgment means 3 and 15 which decide the number of photographed sheets and/or the exposure correction amount of every frame of the automatic bracketing photographing based on the photoelectric output and/or the processing output from the photometry means 1, 11 and 13 and exposure set means 5 and 15 which decide the exposure values of the respective frames based on the number of photographed sheets and/or the exposure correction amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auto-bracketing device for a camera, and more particularly, to automatically setting parameters required for auto-bracketing photography by utilizing the output of multi-photometric means. The present invention relates to an auto bracketing device.

[0002]

2. Description of the Related Art There is known an auto-bracketing device which sequentially shoots a plurality of frames while changing the exposure value by a predetermined amount with respect to one set exposure. In such an auto-bracketing device, for example, by designating the exposure value in the first shooting, that is, the start exposure value, the exposure correction amount for each frame, and the number of frames to be shot, the release button is operated. A plurality of frames are automatically photographed according to the exposure value which is sequentially corrected by the exposure correction amount from the designated start exposure value. Further, such an auto-bracketing shooting function can be built in the camera body, or the back cover of the camera can be provided with the auto-bracketing function by exchanging it with a data back device. it can.

According to such an auto-bracketing device, there is an advantage that a proper exposure or a desired exposure intended by the photographer can be automatically obtained without missing a photo opportunity.

[0004]

However, in such a conventional auto-bracketing device, when the photographer performs auto-bracketing photography, the above-mentioned respective parameters, that is, the number of shots of auto-bracketing and each frame are taken. It is necessary for the photographer himself to set the exposure compensation amount and so on. However, the setting of each of such parameters ultimately depends on the experience and intuition of the photographer, and it may be difficult to perform accurate auto-bracketing photography such as wasting film and being unable to photograph a desired exposure state. ..

In view of the problems in the above-mentioned conventional apparatus, an object of the present invention is to enable automatic setting of each parameter of auto-bracketing photography, improve the operability of setting the parameter, and perform auto-bracketing photography properly. Is to be carried out.

[0006]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, in an auto-bracketing apparatus for a camera which sequentially shoots a plurality of frames while changing an exposure value by a predetermined amount. , A multimeter that divides a subject into a plurality of areas to perform photometry, generates a plurality of photoelectric outputs according to the brightness of each area, and processes the photoelectric outputs to generate a processing output necessary for giving proper exposure. Photometric means 1
And a determination means 3 for determining the number of shots for auto-bracketing shooting and / or an exposure correction amount for each frame based on the values of photoelectric output and / or processing output from the multi-photometry means 1, and the number of shots and / or Alternatively, the exposure setting means 5 for determining the exposure value of each frame based on the exposure correction amount is provided.

Further, the judgment means 3 determines at least the maximum value Pmax of the photoelectric output from the multi-photometric means 1 and the difference between the maximum value Pmax and the minimum value Pmin of the photoelectric output and the number of shots and the exposure correction amount. It is convenient to decide.

[0008]

In the above construction, the multi-photometric means 1 divides the subject into a plurality of areas for photometry to generate a plurality of photoelectric outputs in accordance with the brightness of each area, and at the same time, the photoelectric outputs are processed for proper exposure. Processing output required to give a maximum value Pmax, minimum value Pmin of photoelectric output, average value of a plurality of photoelectric outputs, output value corresponding to proper exposure, difference between maximum value Pmax and minimum value Pmin of photoelectric output , Etc. occur as needed. Then, the determination means 3 determines the number of shots for auto-bracketing photography and / or the exposure correction amount for each frame based on the value of the photoelectric output and / or the processing output from the multi-photometry means 1.
In this determination, for example, the contrast of the subject is determined based on the maximum value Pmax of the photoelectric output, the difference between the maximum value Pmax and the minimum value Pmin of the photoelectric output, and the number of shots and the exposure correction amount are determined. The exposure setting means 5 determines the exposure value of each frame based on the number of shots and / or the exposure correction amount thus determined, and the auto-bracketing shooting operation is performed based on this.

Therefore, each parameter of the auto-bracketing photography, which has been conventionally set by the photographer's own experience and intuition, is automatically set based on the brightness of each area of the subject,
The setting operability of auto bracketing shooting is improved and more accurate auto bracketing shooting is performed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a basic configuration of an auto-bracketing device for a camera according to an embodiment of the present invention. The device shown in the figure comprises a camera body 7 and an auto-bracketing device 9 connected to the camera body 7. In this embodiment, the auto-bracketing device 9 is assumed to be incorporated in the back cover of the camera body 7, for example, but the present invention is not necessarily limited to such a configuration.
Obviously, the auto-bracketing device 9 may be provided in the camera body.

The camera body 7 is provided with a conventionally well-known multi-photometric device 11 and a microcomputer 13 for the camera body which determines an appropriate exposure based on the output from the multi-photometric device 11. A microcomputer 15 is provided in the auto-bracketing device 9, and the microcomputer 15 and the main body microcomputer 13 can communicate data and the like with each other.

In the apparatus shown in FIG. 2, the multi-photometric device 1 is used.
1 divides an object into a plurality of areas for photometry, generates a plurality of photoelectric outputs according to the brightness of each area, and inputs the photoelectric outputs to the microcomputer 13. The microcomputer 13
The plurality of photoelectric outputs are processed to generate a processing output necessary for giving proper exposure. As an example of the processed output,
For example, the maximum value Pmax and the minimum value Pm of the photoelectric outputs
in, the average value, the difference between the maximum value Pmax and the minimum value Pmin of the photoelectric output, and others. The microcomputer 13 calculates an appropriate exposure value necessary for normal shooting based on the photoelectric output and the processing output, and in the normal shooting mode, the camera body 7 based on this appropriate exposure value.
And controls each part in to perform the photographing operation.

On the other hand, when performing auto-bracketing photography, the microcomputer 15 in the auto-bracketing device 9 reads the photoelectric output and the processing output in each area of the photographing screen from the microcomputer 17 in the camera body. .. Then, as will be described in detail later, based on each of these outputs, the shooting screen is classified into a plurality of categories based on its brightness distribution, and in what range the exposure should be adjusted in each category and how many frames should be adjusted. Judge whether or not to shoot. And
Using the information thus obtained, the exposure value of each frame in auto-bracketing photography is calculated and input to the microcomputer 13 on the camera body side. As a result, the microcomputer 13 on the camera body side sequentially performs shooting with each exposure value.

In such a process, as a method of classifying the categories according to the luminance distribution of the subject, the subject is divided into a plurality of regions for photometric measurement as in JP-A-57-82822, and the main light source in each region is measured. It is possible to use a method of classifying the luminances of 1 and selecting an appropriate photometric output according to the luminances. Taking this case as an example, the following classification methods are possible.

That is, assuming that the maximum value of the plurality of photoelectric outputs obtained by the multi-photometer 11 is Pmax, (1) When Pmax ≧ 9: In this case, a considerably bright object such as the sun or Scenes containing bright clouds,
Or it corresponds to a scene that includes the sky in fine weather.
The number "9" represents, for example, 9 EV, but this value can be set to a relatively appropriate value by each camera. (2) When 0 ≦ Pmax <9: In this case, it is a scene such as a general cloudy weather in the daytime or a scene of indoor or evening scene. In addition, more finely 0 ≦ Pma
It is also possible to classify into a slightly darker scene and a slightly brighter scene, such as x <4, 4 ≦ Pmax <9. (3) When Pmax <0: In this case, it is a night view. The automatic bracketing device 9 based on such classification
The processing procedure executed by the microcomputer 15 therein will be described with reference to the flowchart of FIG. First, by half-pressing the release button (not shown) on the camera body,
The program of FIG. 3 is started, and an initial reset is performed in step S0. Each parameter for auto-bracketing shooting, for example, the number of shots n and the exposure correction amount X for each frame are set.
Becomes zero.

Next, in step S1, the proper exposure P out of the processed output from the microcomputer 13 on the camera body side.
_AV , maximum value Pmax and minimum value Pmi of a plurality of photoelectric outputs
Read n information. Then, in step S2, the magnitude of the maximum value Pmax of the photoelectric output is determined. And Pm
If ax ≧ 9, the process proceeds to step S7, and after the number n of exposure frames and the exposure correction amount X which are defined in advance are selected, the process proceeds to step S7.
Proceed to 10 to end the program. In the present embodiment, in step S7, the number of shooting frames n = 7 and the exposure correction amount X = 1.
In this situation, a scene with high contrast is assumed, so that the number of shots is increased and auto-bracketing shooting is performed over a wide exposure range. Obviously, the values are not limited to these values.

Next, in step S2, Pmax <
In the case of 0, it is assumed that a night view or the like is assumed, the process proceeds to step S8, and the number n of shooting frames and the exposure correction amount X which are defined in advance are selected, and the program ends in step S10. In such a case, it is considered possible to make the exposure correction amount X relatively large and reduce the number of frames to be photographed.
= 3, the exposure correction amount X = 1 EV.

In step S2, 0≤Pmax <
In the case of 9, the process proceeds to step S3, and the bracketing exposure area ΔP for auto-bracketing shooting is obtained. ΔP is a value obtained by multiplying the difference between the maximum value Pmax and the minimum value Pmin by the secondary correction amount p. ΔP = (Pmax−Pmin) × p In this way, by limiting the exposure area to the range between Pmax and Pmin, it is possible to efficiently perform auto-bracketing photography only in a necessary area. Further, since the proper exposure of the subject is expected to exist within the range of Pmax and Pmin, a secondary correction amount of 0 <p ≦ 1 is defined to further limit the exposure range of auto-bracketing photography. Although the secondary correction amount is defined as p = 0.8 in the present embodiment, the secondary correction amount is not necessarily limited to this.

After calculating the bracketing exposure area ΔP in step S3, the program proceeds to step S4 to determine whether the maximum value Pmax of the photoelectric output is 4 or more. If Pmax is not 4 or more, that is, 0
When ≦ Pmax <4, the process proceeds to step S5. In this case, it is conceivable that there is little change in the exposure level within the screen even in the expected shooting scene. Therefore, after the number of photographed images is set to be small and n = 3, the process proceeds to step S6. In step S6, the exposure correction amount X per frame is calculated as follows based on the exposure area ΔP and the set number of shots n. X = ΔP / n

As a result, the number of shots n and the exposure correction amount X per frame in the auto-bracketing shot are set, and thereafter the program proceeds to step S10 and ends.

In step S4, 4≤P
If it is determined to be max, the process proceeds to step S9. In this case, 4 ≦ Pmax <9, and it can be considered that the change in the exposure level in the screen is relatively large even in the assumed shooting scene. Therefore, the number of photographed images n = 5 which is larger than n = 3 selected in the step S5 is set, the exposure correction amount X is calculated in the same manner as described above in step S6, and the process proceeds to step S10 to end the program.

In the present embodiment, the number of shots n is set to an odd number, but when the number of shots n is set to an odd number, the same exposure change caps should be shot on both sides around the proper exposure. This is because you can

In this way, the number of shots n and 1 in the auto-bracketing shot is set by the processing shown in FIG.
After the exposure correction amount X for each frame is defined, the microcomputer 15 in the auto bracketing device 9 continues to perform the processing shown in FIG. In this process, the exposure value P ₁ of the first frame in auto-bracketing photography and the exposure value P _n of each frame until the prescribed number of photographed pictures n are successively calculated are calculated.

This process will be described with reference to FIG.
After the processing of FIG. 3 is completed, the processing of FIG. 4 is started, and the initial reset is performed in step S11. The exposure start value P _{1 up} to that point is changed to the exposure values P ₂ , P ₃ , ..., P _{n of} each frame.
Are all cleared. Then, in step S12, the number of shots n, the exposure correction amount X, the proper exposure value P _AV , the maximum value Pmax, and the minimum value Pm obtained by the processing of FIG.
Read in.

Next, in step S13, the exposure value P ₁ at the start of auto-bracketing photography is obtained by P ₁ = P _AV − (1/2) (n−1) · X.

Next, in step S14, the variable N for program processing is set equal to 2. And
In step S15, the exposure value P _{N for the} second and subsequent frames is calculated in a form including the proper exposure value P _AV , so P _N = P
_N-1 + X calculation is performed. Then, after incrementing N by 1 in step S16, it is determined in step S17 whether N is larger than n. If N is not larger than n in this determination, the process returns to step S15 and the processes of steps S15 and S16 are performed.

When N becomes larger than n in step S17, the process proceeds to step S18. In step S18, it is determined whether the maximum value Pmax is greater than or equal to zero and less than 9. If Pmax is not less than zero and less than 9 in the range, the program proceeds to step S21 and ends. In this case, since n and X are particularly defined in the process shown in the flowchart of FIG. 3, the processes of step S19 and step S20 are not performed, and the process directly proceeds to step S21 and the process is completed.

On the other hand, if it is determined in step S18 that the maximum value Pmax is greater than or equal to zero and less than 9, the process proceeds to step S19. Step S19
Then, it is determined whether or not Pmin <P ₁ and P _N <Pmax. This is to determine whether or not both the shooting start exposure P ₁ and the shooting end exposure P _N in the auto bracketing shooting are both within the minimum outputs Pmin and Pmax. If it is determined in this determination that the shooting start exposure P ₁ and the shooting end exposure P _N are between Pmin and Pmax, the process proceeds to step S21 and ends.

On the other hand, if it is determined in step S19 that at least one of the shooting start exposure P ₁ and the shooting end exposure P _N is not within the range defined by Pmin and Pmax, the program is executed. It proceeds to step S20. In step S20, as described above, since the proper exposure value P _AV is expected to be within the range of Pmax and Pmin, the exposure range of auto-bracketing photography is limited to the range of Pmax and Pmin. This makes auto-bracketing shooting more accurate and efficient. Therefore, the exposure correction amount X per frame is multiplied by a constant of 0 <k <1 to reduce the exposure correction amount X, whereby the shooting start exposure P ₁ and the shooting end exposure P ₁
Make _N fall within the range of Pmin and Pmax. Then, the process returns to step S13 again, and the processes from step S13 to step S19 are performed. Such processing is performed in step 19 with Pmin <P ₁ and P _n <Pma.
After repeating until x, the process proceeds to step S21 to end the process. Although k = 0.7 in step S20 in the present embodiment, the value of k is not limited to this as long as 0 <k <1 is satisfied.

By the above processing, the number of shots n in the auto-bracketing shooting, the exposure correction amount X per frame,
The exposure values P ₁ , P ₂ , ..., P _AV , ..., P _N at the time of each photographing were defined. Therefore, the microcomputer 15 in the auto-bracketing device 9 communicates with the microcomputer 13 in the camera body 7 to sequentially transmit the exposure value information from P ₁ to P _N to the camera side for each shooting. The camera body 7 shoots based on the exposure values P _{1 to} P _N , and the auto-bracketing shooting is completed.

[0031]

As described above, according to the present invention, in auto-bracketing photography, parameters such as the number of shots and the exposure correction amount per frame which have been set by the photographer based on experience and intuition are automatically set. Since it can be set, the setting operability of auto bracketing shooting is greatly improved,
Accurate and efficient auto-bracketing shooting is performed.

Further, this function can be easily added to the camera and the auto bracketing device having the conventional multi-photometric exposure control device, and in this case, the photographer can perform the auto bracketing according to the present invention as in the conventional case. It is also possible to manually set each parameter with reference to the automatic setting contents.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a schematic configuration of an auto-bracketing device for a camera according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an auto-bracketing device for a camera according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a processing procedure in the apparatus of FIG.

4 is a flowchart showing a processing procedure in the apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multi-photometry means 3 Judgment means 5 Setting means 7 Camera body 9 Auto bracketing device 11 Multi-photometry device 13 Microcomputer for camera body 15 Microcomputer for auto bracketing

Claims (2)

[Claims] 1. An auto-bracketing device for a camera, which sequentially shoots a plurality of frames while changing an exposure value by a predetermined amount, wherein an object is divided into a plurality of areas for photometry, and a plurality of areas are measured according to the brightness of each area. And a photometric output from the multiphotometric means, and a value of the photometric output from the multi-photometric means. A determination unit that determines the number of shots and / or an exposure correction amount for each frame in auto bracketing photography based on the above, and an exposure setting unit that determines an exposure value of each frame based on the number of shots and / or the exposure correction amount. An auto-bracketing device for a camera, which is provided. 2. The determination means determines the number of shots and the exposure correction amount based on at least the maximum value Pmax of the photoelectric output from the multi-photometric means and the difference between the maximum value Pmax and the minimum value Pmin of the photoelectric output. Claim 1
The auto-bracketing device for the camera described in.