JPH04344608A - Camera system - Google Patents

Abstract

PURPOSE:To automatically control the focal length range of a zoom lens to a range wherein no lens vignetting is occured, to improve the operability, and to prevent a failure in photography due to lens vignetting when the lens vignetting is occurred due to the cutoff of flash light by the lens barrel, etc., of the zoom lens at the time of flash light photography. CONSTITUTION:When a subject B is photographed, a camera main body A inputs data no the motor-driven zoom lens 2 to a microcomputer, which sets the focal length range wherein no lens vignetting is occured according to the data and position information on a flash light emission part 3. The microcomputer automatically drives the lens by a lens driving circuit into the focal length range wherein no lens vignetting is occurred unless a zoom position when a flash light photography mode is set is within the focal length range.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens drive for a camera system with an interchangeable lens and a built-in flash or an external flash.

0002

[Prior Art] Conventionally, when taking pictures with a flash, lens vignetting occurs due to the flash light being blocked by the lens barrel, etc., resulting in insufficient light at the periphery of the shooting screen, resulting in unsuccessful pictures. . Incidentally, in recent years, interchangeable lenses have become larger in both lens diameter and length due to higher zoom ratios, wide-angle zooms, electric power zooms, and the like. On the other hand, flashes are built into the body and are compatible with wide angles, and when used in combination with an electric zoom lens as described above, there is a high probability that lens vignetting will occur during flash photography. Since it is impossible to confirm the occurrence of lens vignetting during shooting, caution should be written in the instruction manual of interchangeable lenses that cause lens vignetting during flash photography to alert photographers in advance. ing.

0003

[Problems to be Solved by the Invention] By the way, since the zoom lens described above can change the focal length, lens vignetting can be avoided by controlling the focal length range of the lens to a range that does not cause lens vignetting. However, it is impossible to set this range by arbitrary zooming operations by the photographer. In addition, interchangeable lenses with electric zoom do not have a means to automatically control the focal length range to a range that does not cause lens vignetting when lens vignetting occurs. There was a problem with inviting photos. The present invention solves the above-mentioned problems. When lens vignetting occurs due to the use of an electric zoom lens, the present invention automatically controls the focal length range of the lens to a range that does not cause lens vignetting, and has good operability. Another object of the present invention is to provide a camera system capable of preventing failed photographs due to lens vignetting.

0004

[Means for Solving the Problems] In order to achieve the above object, the invention of claim 1 provides a camera system that has a built-in flash with an interchangeable lens or that can be equipped with an external flash. a control means for controlling the camera by inputting the above information; a focal length range setting means for setting a focal length range in which lens vignetting does not occur based on the input lens information and position information of the built-in or external flash; Alternatively, a zoom drive means that is located in the lens and drives the lens to zoom; a zoom drive operation means that is located in the camera body or lens that drives the lens to zoom by the zoom drive means; and a flash photography mode setting means for setting the flash photography mode, and when the flash photography mode is set, the control means controls the zoom driving mode when the zoom position of the lens is outside the focal length range set by the focal length range setting means. The lens is driven by means such that the lens is within a focal length range in which lens vignetting does not occur. The invention according to claim 2 is provided with a zoom regulating means for regulating the zoom position that can be input by the zoom drive operation means to be within the focal length range set by the focal length range setting means when the flash photography mode is set. be.

[0005]

[Operation] According to the structure of claim 1, data on the type of lens currently in use is input to the control means, and the focal length range setting means uses this data and the position information of the built-in or external flash. Set the focal length range where lens vignetting does not occur. The control means automatically prevents lens vignetting by the zoom driving means when the flash photography mode is set and the current zoom position of the lens is outside the focal length range set by the focal length range setting means. Drive the zoom within the focal length range. According to the configuration of claim 2, when the flash photography mode is set, the range in which the photographer can set the zoom position using the zoom drive operation means is within the focal length range set by the focal length range setting means. automatically regulated.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A camera with an interchangeable flash and a built-in flash (hereinafter referred to as a camera) according to an embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a side view of the camera according to this embodiment when the electric zoom lens is attached, Figure 2 is a front view of the same camera when the electric zoom lens is not attached, and Figure 3 is a top view of the same camera when the electric zoom lens is not attached. be. In these figures, a camera main body A is composed of a camera body 1 and an exchangeable electric zoom lens 2, and a flash light emitting section 3 is integrally built into the upper surface of the camera body 1. The electric zoom lens 2 includes a lens drive operation unit 4 for the photographer to perform zooming.
is formed. Further, the camera body 1 has a lens signal contact 5 for inputting lens information of the electric zoom lens 2 to the microcomputer 10 (FIG. 4) on the camera body 1 side. Further, the top surface of the camera body A has a flash photography mode selection switch 6 for setting whether or not to perform flash photography, a display section 7 for displaying various data, etc., and a release button 8. .

FIG. 4 is a block diagram of the control system of this camera. In the figure, a microcomputer (μC) 10 mounted on a camera body 1 is a control means that controls an external circuit to perform a predetermined operation and also controls the entire camera. When the photographer presses the release button 8 one step to close the switch S1 and the camera becomes ready for photographing, power is supplied to the microcomputer 10. The lens drive operation unit 4 of the electric zoom lens 2 sends a contact signal corresponding to the operation direction to the microcomputer 10 via the lens signal contact 5.
Enter. A lens circuit (LEC) 11 holds data such as the type of lens, and inputs and outputs data to and from the microcomputer 10. A lens drive circuit (LDC) 12 is a circuit that drives the electric zoom lens 2 by a motor M, and the microcomputer 10 controls the lens drive circuit 12 based on a signal input from the lens operation section 4. The encoder 13 outputs the lens drive amount to the microcomputer 10, and the microcomputer 10 thereby controls the lens drive amount by the lens drive circuit 12.

A focus detection circuit (AFC) 14 is a circuit for measuring a distance to a subject, and outputs distance measurement information to the microcomputer 10. Display circuit (DSP) 15 is microcomputer 1
This is for displaying data such as the setting status of the flash photography mode selection switch 6 on the display unit 7 provided in the camera body A based on the output from the camera body A. Further, the flash circuit (FLC) 16 controls the flash light emitting unit 3, and the microcomputer 10 automatically controls the flash photography mode when the photographer selects the flash photography mode using the flash photography mode selection switch 6, or when the switch S1 is turned on. It becomes operational when the flash photography mode is selected. The microcomputer 10 also includes a focal length range setting means for setting a focal length range in which lens vignetting does not occur based on data such as the type of lens and flash position information, and a zoomable range within the set focal length range. It serves as a functional means for zoom regulation.

Next, lens vignetting during flash photography using the camera body A will be explained with reference to FIG. In the figure, the electric zoom lens 2 used has a focal length a
It is possible to zoom up to section b. Here, when the flash photography mode is selected and the subject B located at the shortest photographing distance R of the lens 2 is photographed, lens vignetting will occur in the shaded area. Therefore, the focal length a~c
The interval is a range in which lens vignetting does not occur. Suppose now that when the flash photography mode is entered, the focal length of the electric zoom lens 2 is in the c-b interval. In this state, lens vignetting occurs, so as an initial operation for flash photography, the microcomputer 10 automatically controls the lens drive circuit 11 to set a focal length a that does not cause lens vignetting.
-C section. Here, the microcomputer 10 regulates that even if the photographer operates the zoom drive operation section 4, the zoom drive operation section 4 can only be driven within the focal length range a to c until the flash photography mode is canceled.

Furthermore, in the same state, the electric zoom lens 2
When the focal length of is already in the a-c interval, the above-mentioned initial operation, that is, the operation of automatically zooming in the a-c interval, is not performed, and control is performed to enable zoom drive within the focal length a-c interval. Note that, assuming that lens vignetting cannot occur when the camera is not in the flash photography mode, the zone in which the zoom drive is controlled is the entire zone from focal length a to b. Further, when the flash photography mode is canceled at some timing, the above-mentioned restrictions are also canceled.

Incidentally, in the above description, lens vignetting that occurs only when photographing a subject at the lens's shortest photographing distance R has been explained, but for a subject at a distance beyond the lens's shortest photographing distance R, the focal length can also be adjusted based on the distance measurement information of the subject. The regulation range can be made variable. Figure 6 shows the shooting distance r (r
>R) shows lens vignetting when photographing a subject C with a flash using the camera body A. In the figure, as the subject position, that is, the photographing distance becomes longer, the focal length range in which lens vignetting does not occur becomes larger, ranging from a to d, compared to when photographing an object at the shortest photographing distance of the lens. Here, the focus detection circuit 14 measures the distance of the subject C in a photographing preparation state by turning on the switch S1. The distance measurement information from the focus detection circuit 14 is output to the microcomputer 10, and the focal length regulation range can be varied.

[0012] The present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above embodiment, a camera with a built-in flash was used, but the present invention can also be applied to a camera to which an external flash can be attached as shown in FIGS. 7 and 8. FIG. 7 is a top view of a camera having an electric zoom lens 2 to which an external flash can be attached, and FIG. 8 is a top view of a camera having a manual zoom lens 21 to which an external flash can be attached. In the previous embodiment, the lens drive operation section 4 was provided on the lens side, whereas in the example shown in FIG. 7, the lens drive operation section 41 is provided on the camera body 101 side.

Furthermore, in the previous embodiment, the electric zoom lens 2 was automatically driven to determine the focal length range that does not cause lens vignetting, but a manual zoom lens 21 as shown in FIG. In a camera, when the zoom lens position is within a focal length range that causes lens vignetting, the display circuit 15 is controlled to display a warning to that effect on the display section 7 provided on the camera body 201, or a warning is issued by a buzzer or the like. All you have to do is As described above, when the manual zoom lens 21 is included in the interchangeable lens group and this lens is attached, it becomes impossible to regulate zooming, so such a warning is effective. In the example shown in FIGS. 7 and 8, a flash shoe 31 is provided on the upper surface of the camera body 101, 201, and a flash signal contact 32 is provided here. FIG. 9 is a diagram showing lens vignetting when the external flash 33 is attached to the camera body 201.

In any of the above embodiments, when setting the focal length range in which lens vignetting does not occur, information on the object distance is also taken into consideration, thereby expanding the focal length range in which zooming is not restricted. be able to. Further, by providing a means for canceling the restriction on the focal length range, it is possible to avoid limiting the range of use by the user. Further, as in the embodiment shown in FIG. 8, by providing a means for issuing a warning without restricting the focal length range, the present invention can also be applied to a manual zoom.

[0015]

[Effect of the invention] As described above, according to the invention of claim 1,
Regarding lens vignetting that occurs when using an electric zoom lens, the lens is automatically controlled to a focal length range that does not cause lens vignetting, based on data such as the type of lens and the position of the built-in or external flash. Therefore, it is possible to automatically avoid the occurrence of lens vignetting that cannot be confirmed at the time of shooting, and it is also easy to operate, and it is possible to prevent failed photos due to lens vignetting. According to the invention of claim 2, in addition to the above effects, when the flash photography mode is set, the zoom drive operation by the photographer is automatically restricted within a focal length range that does not cause lens vignetting. This prevents failed photos due to lens vignetting.

[Brief explanation of the drawing]

FIG. 1 is a side view of a camera with an interchangeable flash and a built-in flash when an electric zoom lens is attached according to an embodiment of the present invention.

FIG. 2 is a front view of the same camera when the electric zoom lens is not attached.

FIG. 3 is a top view of the same camera when the electric zoom lens is not attached.

FIG. 4 is a block diagram of the control system of this camera.

FIG. 5 is a conceptual diagram showing lens vignetting during flash photography of an object located at the shortest distance to the lens.

FIG. 6 is a conceptual diagram showing lens vignetting during flash photography of an object located beyond the shortest lens distance.

FIG. 7 is a top view of a camera with an electric zoom lens to which an external flash can be attached.

FIG. 8 is a top view of a camera with a manual zoom lens to which an external flash can be attached.

FIG. 9 is a diagram showing lens vignetting when an external flash is attached.

[Explanation of symbols]

A Camera body 2 Electric zoom lens 3 Flash light emitting unit 4 Lens drive operation unit 6 Flash photography mode selection operation unit 10 Microcomputer 12 Lens drive circuit

Claims (2)

[Claims] 1. A camera system having a built-in flash with an interchangeable lens or an external flash, comprising a control means for controlling the camera by inputting data such as a type of lens, and the input lens information. a focal length range setting means for setting a focal length range in which lens vignetting does not occur based on position information of the built-in or external flash; a zoom driving means disposed within the camera body or within the lens for driving the lens to zoom; a zoom drive operation means disposed in the body or the lens and configured to perform a zoom drive operation of the lens by the zoom drive means;
a flash photography mode setting means for setting whether or not to perform flash photography, and the control means is configured such that when the flash photography mode is set, the zoom position of the lens is outside the focal length range set by the focal length range setting means. When the camera system is in the camera system, the zoom driving means drives the lens so that the lens falls within a focal length range in which lens vignetting does not occur. 2. The camera is characterized by comprising a zoom regulating means for regulating the zoom position that can be input by the zoom drive operation means to be within a focal length range set by the focal length range setting means when the flash photography mode is set. The camera system according to claim 1.