JPS63287832A - Photographing device - Google Patents

Abstract

PURPOSE:To minimize a camera by providing a receding space for a variable power optical system in the distance measuring luminous flux of a distance measuring system, then altering the action of the distance measuring system according to the recession to the space in the variable power optical system. CONSTITUTION:A lens group 2 for variable power is held by a holding member 4 and freely attached and detached in a photographing luminous flux along a rail 5 in a lens barrel, and the variable power lens group 2 can keep two positions by operating a knob 32. If the variable power lens groups 2 is inserted in the photographing luminous flux and receded outside the distance measuring optical system, a usual measurement of distance is decided and a focusing lens 3 is moved based on the decided result since the lens group 2 is on a telephoto side. In case of a wide-angle side, that means, when the variable power lens group 2 is inserted in the space 30 in the distance measuring optical system, a detection means 34 and a microcomputer 23 detects the position of the variable power lens group and the microcomputer 23 stops the distance measuring actions. Thus, the camera can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a photographing device that is capable of varying a focal length and is equipped with an automatic focus adjustment device.

<Prior Art> Photographing apparatuses in which an optical system for variable magnification is attached and detached within a photographing light beam are well known. Furthermore, there are also known cameras equipped with an automatic focus adjustment device outside the photographing light beam. However, in a camera incorporating the above two devices, when switching the focal length from, for example, the telephoto side to the wide-angle side, a space for retracting the variable power optical system out of the photographing optical path and a focus detection device are required. It is necessary to provide a separate space, which is disadvantageous for cameras that are required to be miniaturized.

<Object of the Invention> An object of the invention is to miniaturize a camera equipped with a variable magnification optical system and an automatic focus adjustment device.

Further, in the present invention, in a photographing device having a variable magnification optical system that is attached to and removed from a photographing light beam and changes the focal length, and a pair of distance measuring systems disposed outside the photographing light beam, a retraction space for the variable magnification optical system is provided. is provided in the distance measuring light beam of the distance measuring system, and further includes a control circuit for changing the operation of the distance measuring system in response to the retraction of the variable magnification optical system into the space.

<Embodiment> FIG. 1 is a configuration diagram of a photographing device according to the present invention. 1,2
．． 3 constitutes a photographic lens, 1 and 3 are main lenses, especially 2.
is a lens group for changing magnification, which is held by a holding member 4 and is detachable into the photographing light beam along a rail 5 inside the lens barrel. A focusing lens 3 achieves focus adjustment by driving a motor 26.

As the focus detection device, a so-called active type detection device is used, which projects infrared or near-infrared light onto the subject and measures the distance based on the reflected light.

The specific configuration will be explained below. 8 is a light emitting element, 6 is a light projecting lens, 7 is a light receiving lens, 9 is a photoelectric sensor that receives projected and reflected infrared light, and is divided into sensor areas 9a and 9b.

16 to 25 shown in the figure are block diagrams for focus detection, 23 is a microcomputer, 16.17 is a synchronization circuit that detects the light reception output from the sensors 9a and 9b in synchronization with the light projecting element 8, respectively; 18.19 is synchronous circuit 16.17
20 and 21 are integrator circuits, 22 is a comparator circuit that compares the integrated outputs of the integrator circuits 20 and 21, and based on the outputs of the comparator circuits, the microcomputer 23 Focus adjustment is achieved by calculating object distance information and transmitting the calculation result to the motor drive circuit 25. Now, when the variable power optical system 2 is inserted into the photographing light beam as shown by the solid line, it is at the telephoto side, and the variable power optical system is inserted between the light receiving lens 7 and the photoelectric sensor 9 as shown by the two-dot chain line. When this happens, the magnification can be changed to the wide-angle side. Next, the switching device for this variable magnification optical system will be explained based on FIG. 2.

By operating the knob 32, the variable magnification lens 1\2 can take two positions. The position indicated by the solid line in Figure 1.2 is for a focal length close to telephoto, and the position is when lens group 2 is retracted to space 30 (double-dashed line in the figure).
is a focal length closer to wide-angle.

Now, when the variable magnification lens group 2 is inserted into the photographing light beam and retracted outside the distance measuring optical system, it is on the telephoto side, so normal distance measurement judgment is performed and focusing lens 3 is used as the judgment result. Move based on.

On the other hand, on the wide-angle side, that is, when the variable magnification lens group 2 is inserted into the space 30 in the distance measuring optical system, the detection means 34 and the microcomputer 23 detect the position of the variable magnification lens group, and the microcomputer 23 detects the position of the variable magnification lens group. Distance measurement operation is stopped.

In this way, if the evacuation space is located between the lens 7 and the element 9, the image on the light receiving element will naturally be blurred as a result of affecting the received light beam, but the focal length at that time will be With a short wide-angle lens, the depth of field is deep and focus adjustment is often not a problem.

In the above embodiments, when the angle becomes closer to the wide angle, the distance measuring operation is stopped at that point, but in the second embodiment, the microcomputer detects the wide angle side and enters the so-called pan focus state. Main lens 1.
It is also possible to control the focus of 3. That is, by appropriately controlling the focus lens of the main lens and the aperture drive circuit 30, the focus lens 3 and the aperture control circuit 30 are operated so as to select a hyperfocal distance that ensures that the distant view is included in the depth of field. You can also narrow down the aperture to increase the depth of field.

Next, FIG. 3 shows the appearance of the entire video camera, with FIG. 3(a) showing a conventional video camera and FIG. 3(b) showing a video camera to which the present invention is applied.

100a and 100b are photographing lenses, 101a and 102a
and 101b and 102b are a pair of ranging systems, 103a and 1
Reference numeral 03b is an operating lever having a structure as shown in FIG. 2 for achieving variable magnification, and 104a and 104b are camera bodies.

As shown in FIG. 3(b) to which the present invention is applied, a part of the space in the light beam of the ranging system is shared as a retreat space for the variable magnification system, which allows the lens barrel to be compacted and the holding can be significantly improved.

In the above embodiments, a so-called active type distance measuring method was adopted as the distance measuring device, but a so-called non-T
A TL passive type ranging method may be adopted. Further, although the light-receiving lens side is used as the evacuation space, it goes without saying that the space on the light-emitting lens side may also be used.

<Effects> As explained above, according to the present invention, the camera can be made smaller, and power consumption can be saved by using the variable magnification optical system or by stopping the ranging operation when the camera is retracted. It also has an effect on points.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of the photographing device of the present invention, Figure 2 is a diagram showing the attachment/detachment mechanism of the variable magnification optical system, and Figure 3 (a).
3 is an external view of a conventional video camera, and FIG. 3(b) is an external view of a video camera to which the present invention is applied. 2 is a variable magnification lens group, and 6 and 7 are distance measuring systems.

Claims (1)

[Claims] (1) In a photographing device having a variable magnification optical system that is attached to and removed from the photographing light beam and changes the focal length, and a pair of distance measuring systems arranged outside the photographic light beam, the retraction space of the variable magnification optical system is What is claimed is: 1. A photographing device comprising a control circuit provided in a distance measuring light beam of a distance measuring system and changing the operation of the distance measuring system in accordance with the retraction of the variable magnification optical system into the space.