JPS59165039A - Variable focusing camera - Google Patents

Abstract

PURPOSE:To switch surely an optical system to telephotographing by setting up a sub-lens system insertion completion detecting switch in addition to a main lens system movement completion detecting switch in the focal distance switching operation of the optical system. CONSTITUTION:The sub-lens system 42 is held by an extender 40 pivotally supported by an extender bar 43, and when standard photographing status shown by a dotted line is switched to telephotographing status, the main lens system moves along an optical axis direction and sub-lens system 42 is inserted into the optical axis as shown by a solid line. A circuit detecting said operation has the shown constitution, a switch 31 is turned on when the main lens is reference photographing status and a switch 32 is turned on in case of telephotographing status. Since a switch 33 is not turned on until the sub-lens system 42 is precisely arranged on the photographing optical axis when the telephotographing status is set up, a sequence circuit 34 in the camera is not turned to operable status.

Description

[Detailed description of the invention] The focal length can be switched between two or more types by moving the main lens system back and forth on the photographing optical axis and moving the sub lens system in and out of the photographing optical axis. This is related to a variable focus camera that can be used.

Cameras other than single-lens reflex cameras, especially 33 mm format lens shutter cameras, generally use VC3. Although a photographing lens having a focal length of S to Gθ is used, it is reasonable to use a lens having a focal length that matches the photographing angle of view depending on the conditions of the subject. Therefore, in order to create a camera that satisfies these functions, a sub-lens system is provided inside the camera in addition to the main lens system, and the sub-lens system is moved in and out of the photographing optical axis as necessary as the main lens system operates. A variety of variable focus cameras have been proposed that can take pictures at different focal lengths, such as general photography using only the main lens system, and photography using an optical system that combines the main lens system and sub lens system.For example, telephoto photography. has been done.

Figure 1 shows an example of the optical system of the variable focus camera described above, which is capable of standard photography and telephoto photography. It is a system. Sθ
θ is the film surface, jθ/ is the shutter, Sθ! is the main lens system, and jθ3 is the sub lens system.

Switching from the standard shooting state shown in FIG. 1(a) to the telephoto shooting state shown in FIG. 1(b) is performed using the main lens system S0,! This is performed by moving the shutter 30/ to the front side of the camera and disposing the sub-lens system Sθ3 behind the shutter 307.

In this way, in variable focus cameras, in order to change the focal length of the optical system, it is necessary to move the main lens system and shutter to the front of the camera, and also to place the secondary lens system behind the shutter. A safety device is provided so that if the switching operation of the optical system is incomplete, that is, incomplete, the sequence circuit within the camera will not operate even if the camera is released. For example, in a variable focus camera having the optical system shown in Fig. 1, the main lens system s
o, 2. A switch is provided that turns on only when the entire unit, including the sub lens system jθ3 and the shutter jθ/, is pulled out or retracted to its proper position in the front-rear direction along the photographing optical axis. If the camera is stopped, the above switch is turned off, disabling the camera's sequence circuit and preventing out-of-focus photos from being taken.

A conventional example of such a variable focus camera will be described below. Figures 2 and 3 are schematic cross-sectional views of a conventional variable focus camera during standard shooting and telephoto shooting, respectively. The lens barrels 3, which are each held in an extension dug, are supported by a lens barrel bar O which is fitted and held by a cover unit gK. The extender "g" is rotatably supported by an extender bar 7 which is fitted into and held by the cover unit.
.

The disposed spring /1lVc is biased toward the front of the camera for a certain period of time, and its tip abuts on the infinite adjustment member /3 screwed onto the cutter unit g. The support bar 2 is fixed to the cover unit g, and the retainer plate // is slidably fitted onto the support bar 7 (-2) and held at two places (guide) (-/θ is Both ends of the cover are fixed to the holding plate //, and the cover unit is fitted into the guide hole so that the cutter unit and the cover unit move along with the support bar 2 in the front and back direction of the camera with -/θ as a guide. Slidable.Infinite adjustment member/S screwed onto lens barrel 3
-L2 is when the cover unit gK is fitted and the shooting optical axis is set.
Distance ring for focusing that can be rotated with a scroll wheel/7
The cam surface of the lens barrel 3 is biased by a spring 6 disposed between the lens barrel 3 and the cover unit. Therefore, by rotating the distance ring/7 by means not shown, the lens barrel 3 is pulled out or retracted along the photographing optical axis L1-L2. There is a bellows between the light shielding plate /9 fixed to the camera body ρθ and the cover unit /, 2
is provided. Patterns A, B and Pattern A',
A board with B' on the front and back, 2.2 is a light shielding plate/9
Contact pieces 23 having patterns C and D are attached to cover units l- and r8, respectively, and patterns A' and C patterns B' and D are used during standard photography (Fig. 2), and patterns B' and D are used during telephoto photography (third In the figure), patterns C and A and patterns B and D are in contact. Note that S is a shutter and 7g is a camera case.

In the variable focus camera configured as above, the second
To change from the standard shooting state shown in the figure to the telephoto shooting state shown in Fig. 3, the cover unit is pulled out in front of the camera, and in conjunction with this pulling operation, the shooting optical axis L1-L2
The extender tag, which had been retracted and locked, is released from the lock by means not shown, rotates around the extender bar 7 by the force of a spring not shown, and is held on the photographing optical axis L1'-L2. Ru. When the cut unit g is completely pulled out from the front side, the contact piece 23
The shiba turns A and B are brought into conduction, and the sequence circuit within the camera becomes operational.

Next, in order to return from the telephoto shooting state shown in Fig. 3 to the standard shooting state shown in Fig. 2, it is sufficient to retract the cover unit g rearward. is retracted from the photographing optical axis again to the outside of =L2, and when the retracting operation is completed, the contact piece 23 connects the blade turns A° and B'' (7 and the sequence circuit becomes operable).

As explained above, in the conventional variable focus camera, the cover unit g is used to check whether the pull-out operation or retraction operation of the optical system for changing the focal length has been completed. 3 is provided to prevent photographing from being performed before the switching operation of the optical system is completed.

However, in order to achieve telephoto shooting, it is necessary to pull out the main lens to the front and place the extension lens with the sub lens 2 on -L2 along the shooting optical axis. It is not designed to determine whether or not the lens is securely held on the photographing optical axis LI L2. Therefore, if there is a failure in the interlocking member that prevents the secondary lens 2 from being placed on -L2 along the photographing optical axis, the VC will be forced to shoot only with the main lens, even though it is telephoto shooting. As a result, there was a risk of taking out-of-focus photos. Moreover, since the sub-lens 2 is disposed inside the camera, it would have a serious drawback if this failure was not noticed.

The present invention has been proposed in view of the above-mentioned problems, and is a variable lens system that detects whether the sub-lens system is reliably placed on the photographing optical axis and enables the sequence circuit in the camera. The purpose is to provide a focus camera.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 7 shows an embodiment of the present invention, showing only the main parts.

The sub-lens 4t, 2 is an extender bar rotatably supported by an extender bar t, 43. is held in The extender pin θ is always biased counterclockwise by a spring, and its protruding portion θa contacts the stopper pin tag in the telephoto shooting state (shown by the solid line in the figure), and the movable contact piece of the switch 33 The switch 33 is turned on by pressing the button. Next, in order to set the standard photographing state, the extender θ is rotated clockwise around the extender bar l13 by means not shown, against the force of the spring gear, and brought into position as shown by the dotted chain line. will be stopped.

Note that the switch 33 has an extension θ at the solid line position 0.
It is turned off when there is nothing else besides elutriation. When changing from this standard shooting state to telephoto shooting mode again, the lock is released and the spring/extend position is released. is rotated to the position shown by the solid line, and the switch 33 is turned on.

FIG. S is a schematic circuit diagram of a camera corresponding to this embodiment. The switches 3/ and 3.2 are connected to the contact piece 23 and the board in FIG. ．． The rear switch and front switch according to 2 are shown respectively, and the terminals A, B, A', and B' also show the patterns A, B, Δ', and B' in FIGS.

The switch 33 and its terminals E and F are the same as in FIG. The 3rd group is the camera sequence circuit.
j is a power supply. With the circuit configuration as shown, the sequence circuit 3g is enabled to operate when either the switch 3/ is on or both the switches 32 and 33 are on. That is, when the main lens is retracted to enter the standard photographing state, the switch 3/ is turned on, and when the main lens is pulled out and the telephoto photographing state is entered, the switch 32 is turned on. Furthermore, when the telephoto shooting state is entered, the switch 33 will not be turned on unless the extension lens is placed securely on the shooting optical axis, so the sequence circuit 34L- of the camera will not become operational. .

FIG. 6 is another embodiment of the present invention, and FIG. 7 is a schematic circuit diagram of a camera corresponding thereto. This example is the same as the example shown in Fig.
This is a powerful version of switch 3 that is turned on when retracted, and by connecting this switch 3 in series with switch 3', the extender θ is reliably retracted from the shooting optical axis during standard shooting conditions. When this occurs, the sequence circuit 3 is activated.

In addition to a switch that detects whether or not the main lens system has completed its movement along the photographing optical axis when switching the focal length of the optical system, the present invention also provides a switch that detects whether or not the main lens system has completed its movement along the photographing optical axis. A switch is provided to detect whether the sub-lens system that goes in and out of the optical axis is securely placed on the photographing optical axis, so it is possible to take photographs without completing the switching operation of the optical system to telephoto photography. This increases the risk of taking out-of-focus photographs.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional example of the optical system of a variable focus camera, Fig. 2 is a schematic sectional view showing a standard shooting state of a conventional variable focus camera, and Fig. 3 is a diagram showing a telephoto shooting state of a conventional variable focus camera. The schematic cross-sectional view shown in FIG.
FIG. 4 is a front view of an extender section of a variable focus camera according to another embodiment of the present invention, and FIG. 7 is a circuit diagram corresponding to FIG. 4. 22... Board 23... Contact piece 3/, 3.2.33.3 O Switch 3'l/Sequence circuit 3j Power supply θ/Extender θa/Protrusion DA/...Spring <14. ．． 2 ・Secondary lens <143・Extender bar stopper pin Fig. 1 Fig. 5 Fig. 7

Claims (1)

[Scope of Claims] A photographing optical system includes a main lens system and a sub-lens system, the main lens system is moved back and forth on the photo-taking optical axis, and the sub-lens system is moved in and out of the photo-taking optical axis. A variable focus camera capable of switching the focal length between two or more types, characterized in that the variable focus camera is provided with a switch for detecting that the sub-lens system is reliably placed on the photographing optical axis.・