JPS6383713A - Automatic daytime synchro flash system for camera - Google Patents

Abstract

PURPOSE:To attain an appropriate exposure and flashed light by comparing the exposure amount that an exposure amount arithmetic means calculates with a sum of steady light and flash light, both of which are reflected from an object, permitting a flash light control means to stop flashing light when the sum reaches the exposure amount and automatically controlling an exposure value and flash light amount. CONSTITUTION:The exposure arithmetic means applies high brightness limit processing to brightness values BL, BC and BR, decides on the exposure value. An exposure control means is connected to that. The exposure arithmetic means is connected to a 2nd zone selection means included in a field classifying means, calculates the prescribed exposure amount, and connects the flash light control means which controls a flash means. The flash control means has a measurement means for photographing as its part. The prescribed exposure amount is a sum of steady light and flash light, and means a prescribed amount determined in order to decide on the stopping of flashing. Thus the exposure value and the flash amount can be controlled automatically, and exposing appropriately, flashing light can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an automatic daytime synchronization system for a camera that allows the camera to automatically perform intra-mouth synchronization photography.

"Conventional technology" Conventionally, this type of technology has been used to determine the exposure gain i.
There are methods that measure and determine ambient light using a batch 1!11 light method such as center-weighted 11111 light, and as an improved version of this, the exposure value is simply calculated from the light metering value.
- Techniques such as adding a predetermined value (for example, IEV) to the standard have also been put into practical use.

"Problem to be Solved by the Invention" However, in the former case, when the main subject (person, etc.) occupies a large proportion of the screen, the background of the main subject becomes over-exposed. In the latter case, although this problem has been improved, if the main subject is not near the center of the screen, there are problems such as the background of the main subject being underexposed. there were.

These problems are due to the fact that the field cannot be classified because the field is photometered all at once.

Furthermore, with regard to controlling the amount of flash, in daytime synchronized photography, it is controlled by the sum of steady light and flash, so classification of the subject is essential, and therefore, satisfactory automatic daytime synchronized photography cannot be performed. The present invention solves these shortcomings and provides an automatic daytime camera system that automatically provides appropriate constant light exposure and flash in various scenes during daytime synchronized photography. The purpose is to provide a synchronized system.

``Means for Solving the Problems'' The gist of the present invention to achieve the above object is, as shown in FIG. In an automatic daytime synchronization system for a camera, the camera includes: a photometer that measures light by dividing a field into a plurality of areas; and an average brightness value and a maximum brightness difference between the brightness values of each area measured by the photometer. a field classification means for classifying a field from the field; an exposure calculation means for calculating an exposure value consisting of a combination of an F number and a shutter exposure time based on the output of the field classification means; and the exposure calculation means. an exposure control means for controlling exposure based on the output of the means; an exposure calculation means for calculating an exposure amount based on the output of the field classification means; The automatic daytime synchronization system for a camera is provided with a flash control means for stopping the light emission of the flash means when the sum of the light and the light reaches the exposure amount.

``Effect'' When performing synchronized photography during the day, the photometer divides the field into multiple regions and measures the light, and the field classification means calculates the average value and maximum brightness of each region. The field is classified using the difference as a parameter, the exposure calculation means calculates an exposure value consisting of a combination of the F number and the exposure time of the shutter based on the output of the field classification means, and the exposure control means based on the output. At the same time, the flash unit emits a flash of light, and the sum of the exposure calculated by the exposure Vt calculation unit based on the output of the field classification unit and the light reflected from the subject of the constant light and the flash is calculated. When the exposure value is reached, the flash control means stops the flash light emission, and the exposure value and flash amount are automatically controlled to ensure proper exposure and flash emission at all times in various scenes. It is designed so that the following can be carried out.

“Embodiment” An embodiment of the present invention will be described below based on the drawings. Each figure shows one embodiment of the invention.

As shown in FIG. 2, this embodiment is implemented using a single-lens reflex camera as a medium, and the figure shows the situation when observing through the camera's finder.

The light flux (in this case, stationary light) that has passed through the photographic lens assembly 2 is reflected by the mirror 4 of the eye reflex camera body l, passes through the focus plate 5 and the pentaprism 6, and a part of it is reflected by the eyepiece lens 7.
The other part is arranged so as to be guided to a photometric means consisting of a condensing lens 8 and a light receiving element 9. The photometering means measures the screen (field of subject) as shown in Figure 3, C, R.
, U, and Jllll in 3 areas excluding the U area.
It is constructed to emit light.

Figure z4 shows the state of the camera during photographing operation, in which the light emitted from the flash device 3, reflected back to the subject, and the constant light both pass through the photographic lens structure 2,
Because Mirror 4 is evacuated.

It reaches the film surface 11. The light is then reflected by the film surface 11 and guided to a photometry f-stage for photographing operation, which includes a condenser lens 12 and a light receiving element 13.

FIG. 1 shows a block diagram of the configuration of the camera's self-fjJE synchronization system. The photometric f-stage includes the photodetector element 1F-9 shown in FIG. 2 and its three output currents IL, Ic, and I.

(The subscripts correspond to the three divided regions, C and H, respectively.) Logarithmically compressed and open F (fi corrected r4 degree value B
It includes means for converting into L, B C, and B R.

The subject classification means includes a first zone selection means for determining an exposure value, which will be described later, from an average brightness value AH calculated by equations (1) and (2), which will be described later, and a maximum brightness difference Δ; and second zone selection means for calculating the amount.

I31 +BC+BR A Je= -□
...(1) Δ= M A X (8
1, BC, 8R)-M I N (B+, day c, B
R)-(2) Exposure calculation step is 1ilF11!1fI
I'iB t, B C, B R is converted into B[(book), Bc(palm), BR(book) by high brightness limit processing, and then the exposure value is determined, and exposure control is also performed. means are connected. Furthermore, here.

Exposure value refers to the amount determined from the combination of F number and shutter exposure time.

The exposure level calculation stage is connected to the second scene selection stage of the object scene classification means, and is connected to the second scene selection stage of the field classification means, and is configured to calculate the predetermined exposure level 1. It calculates t,
Furthermore, a flash control stage for controlling the flash means is connected thereto. The first stage of flash control includes the photometry means for the photographing operation as a part thereof.

The predetermined exposure amount is the sum of steady light and flash light.

A predetermined device established to determine the stoppage of flash 1.

Figures 5 and 6 show the average brightness value Ave and the maximum brightness difference Δ
Exposure value and predetermined exposure IJ using the values of and as parameters, respectively.
This figure shows a diagram of the zone selection means for determining the zone selection method, which was obtained experimentally.

First of all, Figure 5 is a diagram for determining exposure values, N, B
It is divided into three zones: HM (books) and BM (ri).

A I, A 2 and boundary lines n and m of this diagram will be explained next.

Table 1 That is, A1 has a value of ±IJ7 degrees based on 10 (EV), and A2 has a value of about ±11 degrees based on 14-(EV).

Further, the boundary klJ,n is indicated by Ave=A1, and the boundary line m is indicated by Δ=k(Ave A2). However, the constant is +1 or -0,5 based on l.
Takes the value of degree.

In zone N, the average brightness value Av5 is set to the predetermined value A1 (9 to 10E
There is a zone smaller than V (about ASA/4S0100), and this zone is not subject to automatic daytime synchronized photography, and is a general flash photography area at night or in dark places such as indoors. Zone BM(t) indicates an area on the right side of the boundary line m in the figure, and when this zone is selected, the exposure value becomes the average value of the modulus after high brightness limit processing.

Also, zone B HM (t) indicates the area between boundary lines n and m, and when this zone is selected,
The exposure value is the maximum brightness value B H (
t) and the average value B M (t).

Next, FIG. 6 is a diagram for determining the predetermined exposure amount,
XO, X2, X2%, X3y3. It is divided into 5 zones of X4.

A3 to A5 and Δ1 to Δ4 of this diagram are shown below.

Table 2 Table 3 Zone xO is not a target area for daytime synchronized photography as in FIG. 5, but is a general flash photography area at night or in dark places such as indoors. A predetermined exposure Hxo in this zone will be referred to as a standard exposure amount.

Sea 7X2. The predetermined exposure amounts of X2%, X33'l, and X4 are respectively set to X2. X2%, X3371. When expressed as X4, the subscript represents the amount of shift (EV) in the negative direction from the standard exposure amount xO.

For example, if X0=0.1 [sentence xs], then X2% is =2? X2%=XO-23=0.016 [uxs].

In addition, A7 in FIGS. 5 and 6. The value of Δ varies slightly depending on the characteristics ffi of the side light optical system.

Next, the action will be explained.

In the 7th stage of photometry, the output current from the light receiving element 9 I II
I C and I R are logarithmically compressed, subjected to open F value correction, converted into a brightness value B [* B c + B R, and output to the field classification means.

Next, on the one hand, among the brightness values B L, B C, and B R, only those having a brightness value of a predetermined brightness value (for example, 15% EV (ASA/ISO100) or more) are replaced with a predetermined brightness value. , that is, high brightness limit processing is performed. Each brightness value after this high brightness limit processing is
BC('') and BR() are output to the exposure calculation means.

In the field classification means, the brightness values B L I B c , B
The average brightness value Ay2 of a and the maximum brightness difference Δ are calculated, and each zone selection means selects an appropriate zone.

To explain this specifically, when the camera is pointed at a certain scene, the brightness value measured by the photometer is B L = 16EV (hereinafter all ASA/
ISO100) B c=14EV, B *=
Assume that the EV is 15%.

From this brightness value, the average brightness value Ave and the maximum brightness difference Δ are calculated as follows: Δ= 16-14 = 2 [EV] Assuming that it corresponds to 0 point in Figure 6, the exposure value is zone B M
(t), and zone x2% is selected as the predetermined exposure amount.

B, setting the limit value of high brightness limit processing to 15%.
t=15%EV B c-14EV B R”15
3's EV, so the exposure value is as follows. For example, the exposure calculation means may set the F number as an exposure value to 16. Shutter exposure time is 1/125 [S
1 (within the speedlight sync speed) and outputs it to the exposure control means.

Further, the predetermined exposure amount is determined by the exposure amount calculation means as follows: x0 = 0.1 [text x s], then X 2 = X
'o-2-2=0.025 [1xs] is set.

Next, when you release the camera in this state, the F number will be 16.
The exposure time of the shutter is 1/+25[Sl], and the flash means starts emitting light with the shutter fully open. Then, the exposure amount (sum of steady light and flash light) measured by the 411 light means of the flash control stage F is 0.
．． The light emission is stopped when the value reaches 025 [lX-S]. The shooting is completed when the shutter closes.

In daylight synchro photography, it is necessary to match the exposure determined by the shutter speed and aperture value to the background of the main subject. Therefore, in the case of daylight synchro photography, generally good results can be obtained with a high probability if exposure is determined using the uniform light (BM in this embodiment).

However, in the direction where the average brightness value Ave and the maximum brightness difference Δ become smaller, the background tends to be exposed to 10 bars. BHM (*)) is being carried out.

In addition, in this embodiment, as shown in FIG.
, C, R, and U, but the number of divisions is not limited to four, and may be, for example, two, three, five, or more.

Furthermore, although the explanation was given using a TTL flash control type single-lens reflex camera as an example, this is not limited to TTL light control type single-lens reflex cameras. Needless to say, the same applies to things like lens-shutter cameras.

"Effects of the Invention" According to the automatic daytime synchronization system for a camera according to the present invention, when the camera automatically performs daytime synchronization photography, the field of view is divided into a plurality of areas and photometered, and each area is Since the exposure value and flash amount are automatically controlled using an algorithm that uses the average value and maximum brightness difference of the brightness values as parameters, it is possible to always ensure proper exposure and flash emission in various scenes. It becomes possible to do so.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention.
The figure is a cross-sectional view of the viewfinder of a camera equipped with an automatic daytime synchronization system, Figure 3 is a side view of the split screen, and Figure 4 is a photograph of a camera equipped with an automatic daytime synchronization system. A cross-sectional view during operation, FIG. 5 is a zone selection diagram for determining an exposure value, and FIG. 6 is a zone selection diagram for determining a predetermined exposure amount. 1... - Eye reflex camera body 2... Lens structure 3.
... Flash device 4 ... Mirror 6 ... Pentaprism crucible Figure 3

Claims (3)

[Claims] (1) In an automatic daytime synchronization system for a camera that cooperates with a flash unit that emits flash light to optimize daytime photography, the camera comprises a photometer unit that divides a field into a plurality of areas and measures the light; a field classification means for classifying the field based on the average brightness value and the maximum brightness difference of the brightness values of each area photometered by the means; and based on the output of the field classification means, the F number and the shutter an exposure calculation means for calculating an exposure value consisting of a combination with an exposure time; an exposure control means for controlling exposure based on the output of the exposure calculation means; and an exposure amount calculation means for calculating the exposure amount based on the output of the field classification means. A camera comprising: an exposure calculation means; and a flash control means for stopping the light emission of the flash means when the sum of the constant light and the reflected light from the subject of the flash of the flash means reaches the exposure amount. Automatic daytime synchronization system. (2) The exposure calculation means calculates the exposure value with emphasis placed on a higher luminance value among the luminance values of each region as the average luminance value becomes smaller or the maximum luminance difference becomes smaller. An automatic daytime synchronization system for a camera according to claim 1. (3) The automatic daytime synchronization system for a camera according to claim 1, wherein the exposure amount calculation means calculates a smaller exposure amount as the average luminance value becomes smaller.