JPH0585890B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention relates to a camera with a built-in auto strobe to which an external strobe can be attached, and more particularly to an aperture value setting device for setting the aperture of a lens when using a strobe. It is something.

(b) Prior art The camera elements involved in flash photography include the lens aperture, distance to the subject, shutter speed, strobe guide number, film sensitivity, etc. These elements must be set before shooting. Conventionally, various methods have been adopted for this purpose. Among these, conventional methods for setting the lens aperture include the so-called flash-matic mechanism, which automatically changes the aperture in conjunction with the extension of the objective lens, and the aperture specified in advance on the external strobe side. One that transmits information to the camera side to set the aperture on the camera side, or conversely, one that transmits aperture information set on the camera side to an external strobe to regulate the amount of light emitted by the strobe. There are things etc. Furthermore, there is the so-called TTL direct flash control method, which measures and integrates the light transmitted through the photographic lens using a light-receiving element installed on the camera side, and stops the external strobe from emitting light when the appropriate amount of light is received. In this case, the photometric value will include lens aperture information.

These conventional methods have no problems when using an external strobe with a relatively large guide knife, but
Cameras with built-in strobes tend to be more compact due to the emphasis on portability and maneuverability.
It is not possible to incorporate a strobe with a very large guide number, so a strobe with a guide number of about 10 to 12 is usually built in. When using a strobe with such a small guide number, the aperture aperture must be increased to cover the normal shooting distance.For example, the aperture value typically set when using an external strobe F4～
When set to F8, the disadvantage is that you can only take close-up shots at a maximum of 3 meters, and in some cases around 1 meter. For this reason, in a camera with a built-in strobe, it is desirable to set the aperture to a value close to wide open, for example, F2 to F2.8, except in special cases.

However, when manually setting the aperture, there is a risk that the operator may mistakenly set the aperture because he or she is using an external strobe, or may forget the aperture setting operation altogether.

On the other hand, if a configuration were adopted in which the aperture was automatically set to a value close to its maximum aperture, the depth of field would become shallow, resulting in the inconvenience that blurring would easily occur in close-range photography. In addition, when using a camera with a built-in flash that can be attached to an external flash, if the aperture is automatically set by the built-in flash, it may result in overexposure or depth of field when shooting at close range. This results in the inconvenience that the depth becomes shallower, which impedes usability.

(c) Purpose The present invention was made in view of the above circumstances, and provides a camera with a built-in auto strobe to which an external strobe can be attached, which automatically sets the aperture according to the combination of strobes to be emitted when the strobe is used. The object of the present invention is to provide an aperture value setting device for a strobe that can perform the following steps.

(d) Configuration The configuration of the present invention will be explained below based on one embodiment.

FIG. 1 is a circuit block diagram for explaining one embodiment of the present invention. This embodiment shows an example in which the present invention is applied to a camera with a built-in auto-strobe, which has a photometric means including a light-receiving element and can be equipped with an external strobe.

In the figure, on the camera side, there is a strobe light receiving section 1 that measures and integrates the reflected light P from the subject using a light receiving element such as a photodiode, and a built-in strobe IS or camera A light emission stop signal generating section 2 is provided which outputs a light emission stop signal SI to an external strobe OS attached to a hot shoe or the like. The light emission stop signal generating section 2 receives the ASA information AS of the film and an aperture information signal from an aperture control section 3 which is not shown but serves as an aperture control means for receiving a control signal and setting an aperture value, which will be described later. Based on this information, the timing to output the light emission stop signal SI is controlled. The light emission stop signal SI output in this way is also input to the external strobe OS in the same figure, so
External strobe OS can also automatically adjust the brightness. The external strobe OS and built-in strobe IS are not shown, but when charging is completed, external strobe charge detection means outputs a high level (hereinafter referred to as H) external strobe charge completion signal S2 and built-in strobe charge completion signal S3. and has a built-in strobe charge detection means. MPSW is used when automatically setting the aperture value set in the aperture control unit 3 to a predetermined value (hereinafter referred to as program mode)
This is a mode changeover switch for switching between 1 and 2, and a case where the photographer sets the aperture value manually (hereinafter referred to as manual mode).When this switch MPSW is connected to the P terminal and program mode is selected. outputs a signal S4 of low level (hereinafter referred to as L), and outputs a signal S4 of H when connected to the M terminal and manual mode is selected. These signals S2, S3, S
A mode selection circuit 4 serving as a mode selection means receiving the signal S2 outputs a selection signal for selecting an aperture value setting mode in accordance with a combination of output states of these signals S2 to S4. In this mode select circuit 4, G1, G2, G3 are 3-input AND gates, G4 is an exclusive OR gate, G5 is a NOR gate, INV is an inverter,
G6 is an or gate. AND gate G1 outputs an external strobe charge completion signal S2, a built-in strobe charge completion signal S3, and a mode changeover switch.
The inverter INV receives a signal (hereinafter referred to as an inverted signal) obtained by inverting the signal S4 which becomes H/L by the MPSW, and outputs a selection signal S5. Exclusive OR gate G4 receives signals S2 and S3 and outputs its output to one input terminal of AND gates G2 and G3. AND gate G2 receives the output of exclusive OR gate G4, signal S2, and an inverted signal of signal S4, and outputs selection signal S6. AND gate G3 receives the output of exclusive OR gate G4 and the inverted signals of signals S3 and S4, and outputs selection signal S7. NOR gate G5 receives signals S2 and S3 and outputs its output to one input terminal of OR gate G6. The OR gate G6 receives the output of the NOR gate G5 and the signal S4 from the mode changeover switch MPSW, and outputs a selection signal S8. These selection signals S5, S6,
S7 and S8 are input to the aperture value setting means 5. This aperture value setting means 5 includes a program setting section P ₁

Claims (1)

[Claims] 1. A camera with a built-in auto strobe to which an external strobe can be attached has a built-in strobe charge detection means that detects when charging of the built-in strobe is completed and outputs a built-in strobe charge completion signal, and a built-in strobe charge detection means that detects that charging of the external strobe is completed. An external strobe charge detection means outputs an external strobe charge completion signal, and receives both strobe charge completion signals output from the both strobe charge detection means, and converts the charge completion signal from the charge completion signal of only the built-in strobe to the charge completion signal of only the external strobe. The mode selection means includes a mode selection means for outputting a different selection signal depending on whether the charging completion signal or the charging completion signal of both strobes is selected, and a plurality of programs each having a different combination of external light amount and aperture value. an aperture value setting means for selecting one of the programs in response to a selection signal outputted from the means and generating a control signal corresponding to an aperture value based on the selected program; 1. An aperture value setting device for a camera with a built-in auto-strobe, comprising: aperture control means for setting an aperture diameter to the aperture value.