JPS62118328A - Automatic power varying camera - Google Patents

Abstract

PURPOSE:To photograph securely a subject image of desired size from a subject in motion without missing a shutter chance by switching focal lengths of a variable power lens automatically on the basis of information on the distance to the subject and obtaining the photograph of proper size. CONSTITUTION:When the subject at short distance, a range finding signal VAP is larger than VN so both comparators COMP1 and COMP2 output 0 and the variable power lens 4 is moved to its short focus side, so that a photographed image of the subject is not large. Then when the subject is at intermediate distance, MM<VAP<VN so the comparator COMP1 outputs 1 and the comparator COMP2 outputs 0. Consequently, the variable power lens is switched to its long-focus side to prevent the photographed image of the subject from becoming small. When the subject is at long distance, the range finding signal is lower than VF, so both comparator COMP1 and COMP2 output 1 and the focus of the variable power lens 4 is unchanged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an automatic zoom camera with a zoom lens in which the focus of the zoom lens can be switched, such as an autofocus camera or a bifocal camera. .

(Prior art) Auto-focus cameras have been developed and widely used in recent years, but when shooting people at medium or long distances with an auto-focus camera equipped with a single focus lens, the final image of the person is small and difficult to see. Also, when taking pictures of people at close range, there are many problems where the finished photo shows the face too close.

To prevent this from happening, cameras such as single-lens reflex cameras and bifocal cameras with zoom lenses use zoom operations to change the angle of view and adjust the size of the subject image relative to the film to the desired size. However, it is cumbersome to operate because the zoom adjustment and bifocal switching are manual, and it is also cumbersome for the photographer to adjust the zoom and switch the focus while keeping in mind the distance to the subject. If you adjust the zoom for a moving subject while looking through the viewfinder, you may miss a photo opportunity.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to obtain a subject image of an appropriate size in a camera having an automatic magnification function, and to achieve this object. To,
Using distance information to the subject, the focal length of the variable magnification lens is automatically changed according to the distance information, such as using a long focus when the subject is at a medium or long distance, and short focus when the subject is close. Configured.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 shows a distance measuring and focusing system of an interlocking rangefinder camera (rangefinder camera) as an embodiment of an automatic variable magnification camera according to the present invention.

In the figure, l is a subject, 2 is a focusing lens, 3 is a motor that moves the focusing lens 2 in the optical axis direction, and 4 is a concave lens 4a.
The concave lens 4a is moved to the short focus side (indicated by arrow N) by the solenoid 5OL1, and the convex lens 4b is moved by the solenoid 5OL2.
is moved to the long focal length side (indicated by arrow M). 5
is a shutter, 6 is a fixed lens, and 7 is a film.

On the other hand, 8 is a light receiving lens that receives an infrared light beam for distance measurement, and 9 is a known distance detector such as an optical position detector.

In the infrared active ranging method and the dual image synthesis passive ranging method, the ranging signal VAF output from the distance detector 9
Since VAF has a relationship with the subject distance as shown in FIG. 2, the focusing lens 2 is controlled by the AF control device 10 based on this ranging signal VAF.

Reference numeral 11 denotes a zoom program device which controls solenoids 5QL1 and S01, 2 to switch the focal length of the variable magnification lens 4, an example of which is shown in FIG.

Next, the focal length switching operation by the zoom program device shown in FIG. 3 will be explained.

When the subject is at a short distance, the distance measurement signal VAF is greater than VW as shown in Figure 2, so the comparator GOMP
Both I and GOMP2 output "O". As a result, the transistor TRI becomes conductive via the inverter II, energizing the solenoid 5QLI and moving the concave lens 4a through the arrow N.
, and the variable power lens 4 is moved to the short focus side. Therefore, the photographed image of the subject is not a close-up shot.

On the other hand, at this time, the transistor TR3 is rendered conductive by the output of the inverter II, so the base terminal of the transistor TR2 is forcibly grounded, the transistor TR2 is rendered non-conductive, and the solenoid 5OL2 is deactivated.

Next, when the subject is at a medium distance, the ranging signal VAF becomes VW<VAF<VN as shown in Figure 2, so "1" is output from the comparator COMPI, and the comparator CO
"0°" is output from MPZ. As a result, the transistor TRI becomes non-conductive and the solenoid 5OLI is not energized, and the transistor TR2 becomes conductive via the inverter I2, energizing the solenoid 5OL2 and the convex lens 4b.
is moved in the direction of arrow M, and the variable power lens 4 is moved to the long focal point side. At this time, transistor TR3 is in a non-conductive state.

In this way, when the subject distance is intermediate, switching the variable magnification lens to the long focal length side can prevent the photographed image of the subject from becoming small.

When the subject is far away, the ranging signal VAF is less than VF, so the comparators COMPI and COMP2 both output "1", and the transistors TR1, TR2, TR3
are all non-conductive, and both solenoids 5OLI and 5
Neither OL2 operates, so the focal point of the variable magnification lens 4 does not change.

In order to switch the variable magnification lens 4 to a long focal length for long distances and a short focal length for close distances, the level V of the zoom program device IO must be set.
M may be VF.

FIG. 4 shows another embodiment of the zoom program device, in which the variable magnification lens is switched to a long focus only when the subject is far away.

In the figure, when the subject is far away, the distance measurement signal VAF is less than VF, so the comparator COMP3 outputs "0" and the transistor TR4 becomes conductive via the inverter I3. As a result, the solenoid 5OL2 is activated, the convex lens 4b is moved in the direction of arrow M, and the variable power lens 4 is switched to the long focus side. In this way, the subject image becomes relatively large, making it less difficult to see.

To determine whether the main subject is at infinity, set the distance measurement area to the center of the screen, as shown in Figure 5 (a), or on the diagonal of the screen, as shown in Figure 5 (b). and whether the distance measurement information from that distance measurement area is below a predetermined level (see Figure 5 (
In the case of (b)) or no change (in the case of Figure 5 (b))
In this case, it can be determined that the distance is infinite.

In the present invention, the zoom lens may be fixed to the camera body, or may be detachable from the camera body as in an eye reflex camera. In the latter case, the AF control device and zoom program device may be provided on the lens side. It may be provided on the camera side. Furthermore, it goes without saying that the present invention can be applied to a single-lens reflex camera as well as a rangefinder camera as shown in the embodiments.

Further, in the above embodiment, the signal of the zoom programming device is explained as an analog signal, but the zoom programming device may be configured to be operated by a digital ranging signal. Further, the magnification changing operation of the zoom lens can also be realized by a lens moving means such as a motor or a ratchet other than a solenoid.

Further, in the present invention, the magnification of the zoom lens can be changed not only in two types, long and short, but also continuously according to the subject distance. Of course, it can also be applied to conventional manual focus adjustment cameras that are not focus type.
In the former camera, distance information to the subject is obtained from a ranging signal, whereas in the latter camera, distance information is obtained from the position of a distance ring that is rotated by a focus adjustment operation. The focal length of the variable magnification lens may be automatically switched based on the distance information obtained in this manner.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the claims.

For example, as shown in FIG. 6, a camera is provided with a display as shown at 20, and a landscape photography mode can be selected by a button 21. When the landscape photography mode button 21 is pressed, the landscape mode is displayed on the display 20, and at this time, the lens is switched to wide angle even though the subject is far away. That is, in this case, automatic mode is prohibited and photography is performed at a constant wide angle.

Another method is to switch from the automatic mode to the manual mode (landscape photography mode) by pressing the button 21, and in the landscape photography mode, the photographer can manually set the desired focal length. Furthermore, if no photography is performed within a predetermined time after pressing the landscape photography mode button 21 (the release button is not turned on), the mode may be automatically switched to the automatic mode.

Further, although the above embodiment is a linked rangefinder type camera, the present invention can of course be applied to an eye reflex camera or a movie camera such as a video camera. In addition to the external active distance measurement method and the dual image synthesis passive distance measurement method, there is a method that detects whether the focus matches or does not match on the focal plane, a double image synthesis method that uses off-axis light passing through the lens, or an ultrasound method. Any method may be used.

(Effects of the Invention) As explained above, in the present invention, the focal length of the variable magnification lens is automatically changed based on the distance information to the subject, so the subject image may be too small or too large. To obtain a photograph of an appropriate size without any problems, and to surely obtain a photograph of a desired size of a subject without missing a photo opportunity for a moving subject.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a distance measuring and focusing system of an embodiment of an automatic variable magnification camera according to the present invention, FIG. 2 is a diagram showing change characteristics of a distance measuring signal, and FIG.
The figure is a circuit diagram of one embodiment of the zoom programming device used in the distance measuring and focusing system shown in FIG. 1, FIG. 4 is a circuit diagram of another embodiment of the zoom programming device, and FIGS. (
B) shows a different example of the rear range finder, and FIG. 6 shows an example of a display provided in a camera as a modified example of the present invention. DESCRIPTION OF SYMBOLS 1... Subject, 2... Focusing lens, 4... Variable magnification lens, 7... Film, 9... Distance detector, 10...
...AF control device, 11...Zoom program device Patent applicant Konishi Roku Photo Industry Co., Ltd. Agent Patent attorney Hiroshi Suzuki 2nd Figure F J113 Figure M4 Figure M 5 Figure (A) (B) Figure 6

Claims (3)

[Claims] (1) An automatic variable magnification camera characterized by automatically changing the focus of a variable magnification lens based on distance information to the subject. (2) The automatic variable magnification camera according to claim 1, wherein the camera is a camera using a zoom lens having an automatic focus adjustment function. (3) The automatic zoom camera according to claim 1, wherein the camera is a bifocal switching type camera having an automatic focus adjustment function.