JPH0566629U - Camera photometer - Google Patents

Abstract

(57) [Summary] [Object] To provide a photometric device for a camera, which is equipped with a split photometric device and a shooting screen switching device, and which is capable of performing appropriate split photometry according to the shooting screen size. [Structure] Screen size switching means for switching a shooting screen size between a full size screen and a regulated size screen, a photometric region formed corresponding to the full size screen, and a plurality of divided photometric regions, the photometric region being a plurality of regions. A camera provided with a photometric element which is divided into, and which is provided in each of the divided photometric areas, and divided photometric means for performing photometry based on the output of each photometric element,
The divided photometric area is provided with a photometric area selection means for selecting the divided photometric area used for photometry according to the switched screen size, and the divided photometric area selected at the time of the regulated size screen corresponds to the regulated size screen. That was formed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a photometric device for a camera having a split photometric device and a shooting screen switching device.

[0002]

[Prior art and its problems]

 2. Description of the Related Art There is known a camera capable of switching shooting screens, for example, a camera provided with a shooting screen switching device for switching between a standard size (full size) screen and a half size screen, or a panoramic size screen. Since the photometry device of the camera equipped with such a shooting screen switching device is the average photometry or the center-weighted photometry, even if the screen size is switched, the exposure value will not be greatly affected.

However, in recent years, a split photometric device has been developed which divides a photometric area in a photographic screen into a plurality of areas and evaluates a photometric value in each photometric area to determine an exposure condition. The metering area of this split metering (evaluation metering) device covers almost the entire standard (maximum) shooting screen. Therefore, when the size of the shooting screen is changed, the shooting range and the photometric area do not correspond to each other, and the area outside the shooting range is also evaluated, which may cause a large photometric error.

[0004]

[The purpose of the device]

 An object of the present invention is to provide a photometric device for a camera, which is equipped with a split photometric device and a shooting screen switching device, and which can perform appropriate split photometry according to the size of the shooting screen.

[0005]

[Outline of the device]

 In order to achieve this object, the present invention provides a screen size switching means for switching the shooting screen size between a full size screen and a regulated size screen, and a photometric area formed corresponding to the full size screen and divided into a plurality of areas. A camera provided with the photometric area divided into a plurality of areas, the photometric element being disposed in each of the divided photometric areas, and the divided photometric means for performing photometry based on the output of each photometric element, A metering area selection means is provided to select the divided metering area used for the metering by the divided metering means according to the switched screen size, and the divided metering area selected in the above regulated size screen corresponds to the regulated size screen. It is characterized in that it is formed.

According to this configuration, since the divided photometric area is formed corresponding to the switchable photographing screen, even if the photographing screen size is changed, the divided photometric area corresponding to the changed screen size is used for photometry. As a result, accurate metering is possible regardless of the screen size.

[0007]

【Example】

 The present invention will be described in detail below with reference to illustrated embodiments. FIG. 2 is a sectional view showing an embodiment in which the present invention is applied to a single lens reflex camera. In this camera, a subject light flux that has passed through the taking lens 11 is imaged via a mirror 12 on a focusing plate 14 placed on a surface equivalent to the film surface 13. The photographer observes the image through the pentaprism 15 and the eyepiece optical system 16. The photometric lens 17 arranged above the rear part of the pentaprism 15 uses the subject image on the focusing plate 14 as a secondary light source to project the image on the evaluation photometric element 18 in a reduced scale.

Between the shutter mechanism 19 and the aperture frame 203, a pair of light-shielding plates 204, 205 of the screen size switching means 21 for closing the upper and lower parts of the standard screen to form a panorama size screen is arranged. ing.

As the screen size switching means 21, FIG. 3 shows an embodiment in which the upper and lower parts of the photographing screen are covered with a light shielding plate. A pair of light-shielding plates 204 and 205, which are longer than the width of the aperture frame 203, are disposed outside the upper and lower sides of the aperture frame 203 that regulates the full-size screen. One end of each of the pair of shading plates 204, 205 is slidably guided by a guide plate 206 extending in the lateral direction of the screen. A pair of nuts 207 and 208 having reverse threads are fixed to the other ends of the light shielding plates 204 and 205. These nuts 207 and 208 are respectively screwed to the reverse threaded portions 209a and 209b of the shaft 209 provided outside the other short side of the aperture frame 203 and in parallel with this short side. Therefore, when the shaft 209 rotates, the light shielding plates 204 and 205 move in parallel in the panorama size forming direction in which they approach each other or in the standard size screen forming direction in which they separate from each other according to the rotation direction.

The shaft 209 is rotationally driven by a motor 213 via reduction gear mechanisms 210, 211 and 212. The motor 213 is driven by the drive control circuit 215 in response to the switching of the screen size selection switch 214, and drives the light blocking plates 204 and 205 to the standard size screen position (full size screen position) or the panorama size screen position. At the panorama size screen position, the light blocking plates 204 and 205 shield the standard size screen from light by a predetermined width above and below, and regulate the upper and lower sides of the panorama size screen by the edges 204a and 205b. Further, the limit switches 216, 217 detect that the light shielding plates 204, 205 have reached the normal screen size position or the panorama size screen position, and the drive control circuit 215 is stopped by this detection. The limit switches 216 and 217 also function as stoppers for the light shielding plates 204 and 205.

FIG. 1 shows an example of setting the divided photometric areas of the evaluation photometric element 18. This evaluation photometric element 18 is provided with 13 independent divided photometric areas. The divided photometric area A is provided in the central portion, the divided photometric areas B1, B2, C1 and C2 are provided around the divided photometric area A, and the external divided photometric areas are provided further outside. Regions D1, D2, E1, E2, F1, F2, G1 and G2 are arranged. A photometric element is provided in each of the divided photometric areas A to G2, and each photometric element outputs an electric signal corresponding to the amount of received light. The above 13 divided metering areas A to G2 are almost the same as all the 13 divided metering areas A to G2 in the case of the standard size screen (full size screen), and the upper and lower divided metering areas F1 in the panorama size screen. The divided photometric areas A to E2 excluding G2 to G2 are formed so as to substantially coincide with each other. Therefore, in evaluation metering, all the divided photometric areas A to G2 are used for the standard size screen, and some of the divided photometric areas A to E2 are used for the panoramic size screen to adjust the size of the screen. Accurate evaluation metering is possible.

FIG. 4 shows a control block of an embodiment of the present invention which enables proper evaluation photometry even on the panorama size screen. The exposure control means 30 has a divided photometry area (photometry element) selection means 31, an evaluation photometry calculation means 32, and an exposure factor setting (determination) means 33. To the divided photometric area selecting means 31, the luminance signal from the 13 divided photometric areas A to E2 and the switching signal from the screen size switching means 21 are input.

When the standard size screen is selected by the screen size switching means 21, the divided photometric area selecting means 31 outputs all signals from all the divided photometric areas A to G2 to the evaluation photometric calculating means 32. . Then, the evaluation photometry calculation means 32 calculates the subject brightness (appropriate exposure value) by the evaluation photometry algorithm 50 which gives a predetermined weight to the signals of the respective divided photometry areas A to G2, and the exposure factor setting means 33 calculates the subject brightness. The exposure factor (shutter speed and aperture value) is calculated based on subject brightness, film sensitivity, and the like.

On the other hand, when the panorama size screen is selected, the divided photometric area selection unit 31 selects the specific divided photometric areas A, B1, B2, C1, C2, D1 corresponding to the panorama size screen. The outputs of D2, E1 and E2 are output to the evaluation photometry calculation means 32. Then, the evaluation photometry calculation means 32 calculates the subject brightness (appropriate exposure value) by the evaluation photometry algorithm 60 that uses only the signals of the specific divided photometry areas A to E2 and weights these signals in a predetermined manner, and then performs exposure. The factor setting means 33 calculates an exposure factor based on the calculated subject brightness and the like.

FIG. 5 is a flow chart showing the above operation, but normally this operation is controlled by a microcomputer mounted on the camera. First, it is checked whether the selected screen size is standard. When the screen size is standard size, all the divided photometric areas A to G2 are selected, the subject brightness is calculated by the evaluation photometric algorithm 50, and the exposure factor is calculated. Ask for. On the other hand, when the screen size is the panorama size screen, specific divided photometric areas A to E2 are selected, and the subject brightness is calculated by the evaluation photometric algorithm 60 to obtain the exposure factor.

As described above, according to the present embodiment, when the screen size is switched to the panorama size screen, some of the divided photometry areas A to E2 that match the panorama size screen are selected, and the selected split photometry is selected. Since the exposure factor is set by performing the evaluation photometry by the algorithm 60 corresponding to the area, it is possible to perform the appropriate evaluation photometry and the proper exposure regardless of the screen size.

Although the present invention has been described based on the illustrated embodiments applied to a single-lens reflex camera, the present invention is not limited to these. The screen size is not limited to this panoramic size screen, and may be a half size, for example. For example, in the case of half size, the divided photometric areas are formed or arranged so as to match the shooting screen. Further, it can be used for a lens shutter type camera, and the number and arrangement of divided photometric areas are not limited to this. Also, the screen size changing means 21 is not limited to the configuration of the illustrated embodiment, and is not limited to the configuration of mechanically regulating the film surface. For example, the standard size screen may be used for shooting, and an unnecessary screen may be exposed by light when the film is wound, or an optical mark for identifying that panoramic shooting is performed may be exposed by the light on the film.

[0018]

[Effect of the device]

 As is apparent from the above description, in the present invention, in a camera equipped with a split photometry device and a shooting screen size switching device, the split photometry area used for photometry is formed corresponding to the switchable screen size. Regardless of size, accurate metering and therefore proper exposure is possible.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a photometric element of a split photometric device of the present invention.

FIG. 2 is a sectional view showing a main part of a single-lens reflex camera equipped with an embodiment of the present invention having the same photometric device.

FIG. 3 is a front view showing an embodiment of a screen size changing unit applied to the same-eye reflex camera.

FIG. 4 is a block diagram showing the configuration of an embodiment of the photometric device of the present invention.

FIG. 5 is a flowchart illustrating the operation of the present invention.

[Explanation of symbols]

 13 screen size switching means 18 evaluation photometric device 21 screen size switching means 30 exposure control means 31 divided photometric area selection means 32 evaluation photometric calculation means 33 exposure factor setting means

Claims (3)

[Scope of utility model registration request] 1. A screen size switching means for switching a shooting screen size between a full size screen and a regulated size screen, a photometric area formed corresponding to the full size screen, and a plurality of divided photometric areas. A photometric element arranged in
A camera provided with divided photometry means for performing photometry based on the output of each photometry device, wherein the divided photometry area used by the divided photometry means for photometry is selected according to the switched screen size. A photometric device for a camera, characterized in that selection means is provided, and a divided photometric area selected at the time of the regulation size screen is formed in correspondence with the regulation size screen. 2. The camera photometric device according to claim 1, wherein the divided photometric means changes the weighting of each photometric element used for photometry in accordance with the switched screen size. 3. The camera photometric device according to claim 1, wherein the restricted size screen to be switched is a panoramic size screen or a half size screen.