JPS6388533A - Object distance display device for lens system - Google Patents

Abstract

PURPOSE:To display object distance by detecting the relative distance between a rear lens system and an image pickup element from the position of the rear lens system or image pickup element by a 1st sensor and then focal length from the position of a zoom system by a 2nd sensor, and calculating the distance of an in-focus object from their detection signals. CONSTITUTION:The 1st position sensor 36 detects the position of the rear lens system 30c and supplies the digital detection signal of a digital value corresponding to the movement distance x2 of the rear lens which is the relative distance between the rear lens system 30c and image pickup element 31 to a computing element 35, and the 2nd position sensor 37 detects the position of a zoom system 30b and supplies the detection signal of a digital value corresponding to the focal length (f) to the computing element 35. The computing element 35 is initialized when powered on and substitutes the output digital value of the position sensor 37 which is the position of the zoom system 30b into a variable FNE. Then, the variables FNEW and FOLD are compared and supplied to a display driving circuit 45 to generate a display signal, which is supplied to a display device 46. Consequently, the distance of an subject put in focus by a lens system is accurately found and displayed and the operability and recognition performance are improved.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a subject distance display device for a lens system.
The present invention relates to an object distance display device for a lens system that performs focusing by varying the relative distance between a rear lens system and an image sensor. 2. Description of the Related Art In a conventional lens system, a scale 2 is attached to a focus ring 1 as shown in FIG. 7, and focusing is performed by rotating the focus ring 1 in the direction of an arrow 1. , ) means line 3
By reading the scale 2 indicated by , I was able to find out the distance to the subject that was in focus. However, as shown in FIG. 8, some recent lens systems use, for example, a rear lens system to adjust focus instead of moving the front lens system using a focus ring. In FIG. 8, the zoom lens 10 is composed of a curved lens system 10a, a zoom system 10b, and a rear lens system 10c. When the automatic focus adjustment mode is set by the switch 11, the output error signal of the autofocus circuit section 12 is supplied to the motor 13. Further, when the switch 11 is set to the manual focus adjustment (mani-al focus) mode, the power focus circuit 14 is switched to the close direction switch 15,
An error signal is supplied to the motor 13 when the infinity direction switch 16 is opened. Tanabata 13 adjusts the rear lens system 10c according to the supplied error signal.
move. As a result, automatic fJJ and manual focus adjustment are performed. Problems to be Solved by the Invention When focusing is performed by moving the rear lens system 10c in this way, the subject distance also changes depending on the position of the zoom system 10b, making it impossible to display the subject distance and resulting in poor operability. There was a problem with it being bad. The present invention has been made in view of these points.
The object of the present invention is to provide a device that displays object distance. Means for Solving the Problems In the first invention, the first sensor υ detects the relative distance between the rear lens system and the mud & element from the position of the rear lens system or the imaging element. The second sensor detects the focal length from the position of the zoom system. The performance means calculates a focused object distance from the detection signals of the first sensor and the second sensor. The display means displays the subject distance calculated by the calculation means (
j Now. In the second invention, the first sensor is a rear lens system or

【Yo!
The relative distance between the rear lens system and the image sensor is detected from the position of the i-image element. The second sensor detects the focal length from the position of the zoom system. The third sensor 1) detects the aperture value from the opening and closing of the lens aperture. Stage 01 extracts a focused object distance range from the detection signals of the first sensor, the second sensor, and the third sensor. The display means displays the subject distance range produced by the display means. In the invention, the subject distance range calculated from the relative distance, focal length, and aperture value is displayed. Embodiment FIG. 1 does not show a block system diagram of the first embodiment of the apparatus of the present invention. The zoom lens 30 is composed of a front lens system 30a, a zoom system 30b, and a rear lens system 30c.The zoom lens 30 sends an image to the lla&i lens 31, and the signal photoelectrically converted by the image sensor 31 is converted into a video signal. circuit 32
Here, the signal is converted into a video signal and output from the terminal 33, and is also supplied to the focus control circuit 34. )
The t-cass ff, II control circuit 34 extracts the high frequency component of the video signal and generates and operates a digital error signal 8 for moving the rear lens system 30C in a direction in which the high frequency component is suspended. It is fed into the mouthparts 35. Here, front 1 system 30a, zoom system 30b, rear lens system 30c
If we consider this as an A-lens, it can be expressed as shown in FIG. In the figure, ■ is the subject, ■ is the image, and l−(+,
H2 is the first. 2nd 1 fish, "1," 2 represents the first and second focal points, f is the focal length, ×2 is the rear lens movement distance, U is the subject distance, and δ is the first and second focal points. The distance between the points can be calculated as a function of the focal length f using the following formula: δ=a, +a, -f+a2IIf2+a3-f3 In Fig. 2, the following imaging formula is 1! based on the focal point.
7. X+ ・X2−f2 −=・(1) Also,
The following equation is clear from the drawing. X, +X2 +2- f-)-δ= u -...
-(2) From formulas (1) and (2), U=Gz (f, X2) =x2+2-f'+δ+f2/X2--■X2' =Q
+ (f, U) = 1/2 (-(δ+2・f-U)...(4) Returning to FIG. 1, the first position sensor 36 is located at the rear lens system 30c. After detecting the position U, the rear lens system 30c and the image sensor 3
supplying a detection signal of a digital value corresponding to the rear ball moving section 111f x 2, which is the relative distance from 1 to the arithmetic unit 35;
The second position sensor 37 detects the position of the zoom system 30b and supplies a digital value detection signal corresponding to the focal length f to the Ω operator 35. The volume 40 is for manual focus adjustment, and the contact 40
Slide a to adjust the focus. The switch 41 is an automatic/manual switching switch. The voltage output from the contact 40a of the volume 40 is the A/D
A converter 42 converts it into a digital signal and supplies it to an arithmetic unit 35, and a switching signal from a switch 41 is supplied to an arithmetic f3 converter 35. The performance frame device 35 operates as shown in FIG. In the figure, when the power is turned on, initialization is performed (step 50), and the zoom system 3
Put the output digital value of the position sensor 37, which is the position of 0b, into the variable FNEW (step 51), c:17)
It is determined whether zooming has been performed by comparing ffl variables aFNEW and FOLD (step 52), and when the two match for non-zooming, the volume output from the A/D converter 42 is read and entered into the variable VOL (step 53). . Thereafter, the mode is determined based on the switching signal of the switch 41 (step 54). Here, if the automatic focus adjustment (autofocus) mode is selected, an error signal from the focus control circuit 34 is read (step 55), a motor control signal is generated from this error signal, and the motor control signal is supplied to the motor driver 43 shown in the first figure. Step 56), after which the process moves to step 51. In response, the motor driver 43 supplies a drive signal to the motor 44, and the motor 44 rotates forward or reverse to move the rear lens system 30c toward the image sensor 31 or toward the zoom system 30b, and in response to automatic focus adjustment (autofocus ) action is performed. After this, put the output digital value of the position sensor 36, which is the position of the rear lens system 30c, into the variable
), the focal length of the variables FNEW and Then, the process moves to step 51. The display drive circuit 45 generates a display signal for displaying this object distance U and supplies it to the display 46. Display 46
For example, 7 segments L and E as shown in FIG. 4(A)
D, and numerically displays the subject distance U mentioned above. The display 46 is a meter that displays the subject pressure mu as shown in FIG. 4(B), a meter as shown in FIG. 4(C),
(D) As shown in each figure, among the plurality of display elements, the display element A corresponding to the object distance U is turned on to measure the object pressure lIM.
It may also be one that displays iU. If it is the manual focus adjustment (manual focus) mode at step 54 in FIG. 3, the rear lens movement distance x 2 is calculated and entered into the variable XNEW (step 60). After this, an error signal 17 is generated from the value of the rear lens moving part flr . As a result, the rear lens moving unit 1iIIIX2, that is, the in-focus subject distance is varied in accordance with the volume output. Furthermore, using the focal length and rear lens movement distance of the variables FNEW and
is supplied to the display drive circuit 45 (step 63), and the process moves to step 51'! ] Ru. Further, when it is determined in step 52 that zooming has been performed, the output digital value of the position sensor 936, which is the position of the rear lens system 30c, is entered into the variable X0LD (step 6
4) After this, perform :lri in equation (4) using the value of U and the rear ball movement distance of variables 65). After this, the rear ball moving distance x of the variable XNEW,
An error signal is obtained from the chain of the detection signals of the position sensor +J-36 and the Tanabata control signal is generated from this error signal to move the rear lens system 30G (step 66). This corrects out-of-focus during zooming. Back ball type 30c
When performing focus adjustment based on the relative distance between the image sensor 31 and the image sensor 31, the above correction is necessary. After this, the value of the variable FNEW is put into the variable FOLD to update the position value of the zoom system 30b (step 67).
The process moves to step 51. In this way, it becomes possible to display the object distance, which was previously impossible, and improves operability and recognition. Of course, it can also be used simply as a distance meter. Figure 5, No. 1, shows a block system diagram of a second embodiment of the device of the present invention. In the figure, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. In FIG. 5, an aperture sensor 938 (third sensor) t detects the opening/closing degrees of the three apertures and supplies a digital aperture lens 1 to the zero operator 35. In steps 59 and 63 shown in FIG. 3, the aperture device 35 calculates the depth of focus corresponding to the aperture value and focal length obtained by the aperture sensor 938, and uses the subject stop 11 ( '' and the depth of focus to obtain the in-focus subject ratio tII range and supply it to the display signal generator 47. The display signal generator 47 generates a display signal for displaying the subject distance range and sends it to the mixing circuit 48. The mixing circuit 48 mixes the display signal with the video signal output from the video circuit 32 and supplies the mixture to the electronic viewfinder 49.As a result, the image displayed on the electronic viewfinder 49 has the image shown in FIG. The in-focus object distance range is displayed as shown in .> Since the in-focus object distance range is displayed in this way, the user can more accurately know the image transport state. In addition, in the apparatus shown in Fig. 5, the subject distance fit range is set to 1!? f, and the subject distance U is set as is in Fig. 6 (B).
It may also be displayed on the electronic pew finder 49 as shown in (C). Furthermore, the subject stop muffi, for example, 1m, ~2m
If so, display as shown in Fig. 6(D), and 2TrL~
If it is 5 m, display as shown in Figure 6 (E), and 5 Tr.
If it is L-infinity ((1)), a display as shown in FIG. 6(F) may be made. In this case as well, since the focal length is displayed on the electronic viewfinder 49, there is no need to provide a dedicated display 346 as shown in FIG. Note that automatic focus adjustment control is not limited to the method performed by detecting the high frequency component of the video signal, and may be controlled using any other method, and is not limited to the above embodiment. Note that the developing element 31 may be moved instead of moving the rear lens system 30c by the motor 44. In this case, the position sensor 36 detects the position of the image sensor 31. Effects of the Invention As described above, according to the first invention, even if the relative distance between the rear lens system and the ll3 image Mizuko is varied and the position of the zoom system is varied, the subject distance that is in focus with the lens system can be maintained. It has features such as being able to accurately determine and display information, and improving cognition and cognition. Further, according to the second invention, the in-focus object stop I11
It has features such as being able to accurately determine and display the range, and further improving operability.

[Brief Description of the Drawings] Figures 1 and 5 are block diagrams of each embodiment of the device of the present invention, Figure 2 is a diagram for explaining the principle of the zoom lens shown in Figure 1, and Figure 3 is a diagram for explaining the principle of the zoom lens shown in Figure 1. 1-Chart, FIG. 4,
Each figure shows an embodiment of the display in position A of the present invention, FIG. 7 is a diagram for explaining object distance display of a conventional lens system, and FIG. 8 is a block diagram of an example of a conventional device. be. 30...zoom lens, 30a...front lens system, 30b
. . . Zoom system, 30c . . . Rear lens system, 31 . Aperture sensor, 39...Aperture, 40...Volume, 41...
Switch, 43...Motor driver, 44...Motor, 45...Display drive circuit, 46...Display device, 47
...Display signal generator, 48...Mixing circuit, 49...
・Electronic viewfinder, steps 50-67. Patent applicant: Victor Japan Co., Ltd. Figure 1 Figure 3 Figure jI6

Claims (2)

[Claims] (1) A subject distance display device for a lens system that performs focusing by varying the relative distance between the rear lens system and an image sensor of a lens consisting of a front lens system, a zoom system, and a rear lens system, a first sensor that detects the relative distance from the position of the rear lens system or the image sensor; a second sensor that detects the focal length from the position of the zoom system; and each of the first sensor and the second sensor. 1. A subject distance display device for a lens system, comprising a calculation means for calculating a focused subject distance from a detection signal, and a display means for displaying the subject distance calculated by the calculation means. (2) A subject distance display device for a lens system that performs focusing by varying the relative distance between the rear lens system and an image sensor of a lens consisting of a front lens system, a zoom system, and a rear lens system, A first sensor that detects the relative distance from the position of the rear lens system or image sensor; a second sensor that detects the focal length from the position of the zoom system; and a second sensor that detects the aperture value from the degree of opening and closing of the aperture of the lens. a third sensor that calculates an in-focus object distance range from the detection signals of the first sensor, the second sensor, and the third sensor; 1. A subject distance display device for a lens system, comprising display means for displaying a range.