JPH03119333A - Photographing device - Google Patents

Abstract

PURPOSE:To accomplish high-definition image pickup in a photographing device in which a thin plate glass is used as a half mirror by performing focusing so that a photosensitive element may be positioned at a corresponding image- forming position by making a direction where the image resolution of the photosensitive element is higher relate to the direction of a plane where the deviation of the image-forming position occurs. CONSTITUTION:In the case that the direction where the image resolution in the horizontal or vertical scanning direction of a CCD 8(the photosensitive element) is high is along the direction of a 1st plane group alpha very much, the CCD 8 is positioned at the 1st image-forming position P1. In the case that it is along the direction of a 2nd plane group beta very much, the CCD 8 is positioned at the 2nd image-forming position P2. The relative posture and position of the thin plate glass 2 for thus positioning the CCD 8 and the CCD 8 are set by a control means, a motor driving circuit and a driving means consisting of a driving motor and an AF driving part. Thus, the photographing device using the thin plate glass, which can sufficiently achieve the performance of the image resolution of the photosensitive element, is obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a photographing device, more specifically, a photographing device using a thin plate glass, which is a thin glass, for an optical path splitting half mirror of an imaging optical system. The present invention relates to a photographing device comprising means for setting the relative attitude and position of a glass and a light sensitive element.

[Prior Art] In the above-mentioned photographic device using a shim plate glass for the half mirror, the focus position of incident light on horizontal and vertical planes related to the inclination direction differs depending on the inclination angle and thickness of the shim plate glass. It's coming. Therefore, conventionally, the imaging surface of a film or an imaging device, which is a photosensitive element, is located at the average position of both of the focus positions.

[Problems to be Solved by the Invention] First problem regarding the difference in focus position for incident light on horizontal and vertical planes in a photographing device using the above-mentioned thin plate glass.
This will be explained in detail with reference to Figures 3 to 15.

As shown in FIG. 13, the photographing light beam is taken into the photographing device along the optical axis 0 via the ticking lens 101,
A thin plate glass 102 installed obliquely at an inclination angle θ with respect to the optical axis O (inclined with respect to the vertical direction) branches the optical path into a first optical path 0' and a second optical path A, and the first optical path O'
The light forms an image at a point P on the image sensor 103, and the light on the second optical path A is used for the finder.

Here, each plane is defined. First, a plane that includes the optical axis 0 within its own plane and is parallel to the second optical path A at an inclination angle θ is defined as a first plane α.

A group of planes parallel to is defined as a first group of planes α. Also, optical axis 0
a first plane α. The plane orthogonal to the second plane β
and its plane β. The plane group parallel to is defined as the second plane group β. The incident light along the plane group α is assumed to be LA, and the incident light along the plane group β is assumed to be LB.

Since the shin plate glass 102 is present in the photographing optical path, the focusing position of the image changes due to the bending action of the shin plate glass.Furthermore, since the shin plate glass 102 is disposed obliquely to the optical axis O, A difference occurs in the positions of the focal planes of the incident lights Lt and Ls. 14th
The figure shows the focus positions of the incident lights LA and LB, where the focus position Po is when there is no shin plate glass 102, and the focus position 1i! P1 indicates the focus position caused by the incident light LA on the α plane when a thin plate glass is used, and furthermore, the focus position P2 indicates the focus position due to the incident light Lo on the β plane when the thin plate glass is used. Note that dl indicates the distance from point P to P, and d2 indicates the distance from point Po to IP2. Further, the above-mentioned incident light is assumed to be a luminous flux from the same subject.

The above state can be expressed as MTF (Mod) for any spatial frequency.
ulation Transfer Function
This will be explained with reference to FIG. 15, which is a graph showing a change in the defocus amount (imaging position) of the on value. The above MTF values show a peak at each focus position, and when the shin plate glass 102 is not used, M for the α-merchandising incident light when Mo1 shin plate glass is used, and M2 for the 8-plane incident light. P indicates the change in Ml TF value, respectively. , Pt, and P2 are the respective focus positions.

Since the shin plate glass 102 is provided obliquely as described above, the focus positions P and P of the incident light beams Lp, LB are shifted by the distance dl-d22 (-δ). Therefore, as already mentioned, in conventional photographic devices, the imaging plane of the image sensor or film, which is a photosensitive element shown in FIG. 13, is set at an intermediate position between positions P1 and P2, and the The optical system was designed to keep the light out of focus to the same extent. However, in a general image pickup device that is a photosensitive element, such as a CCD, the resolution is different in the horizontal and vertical directions corresponding to the α plane and β plane. Therefore, as in the conventional case, the position P1. Setting the imaging surface at an intermediate position of P2 means that the high resolution performance of the image sensor in the direction of high resolution cannot be fully utilized.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to perform focusing of an imaging optical system in association with the direction of high resolution of the photosensitive element and the above-mentioned α plane or β plane, so as to sufficiently improve the resolution performance of the photosensitive element. To provide a photographing device using a thin plate glass that can be used in a variety of ways.

[Means and effects for solving the problems] The photographing device of the present invention is inserted into a predetermined imaging optical system at a predetermined inclination angle with respect to the optical axis of the imaging optical system, and A thin plate glass is used that emits a part of the incident light into a first optical path on its output side and branches the other part of the incident light into a second optical path with a reflection angle corresponding to the incident angle of the incident light. a photographic device in which a light-sensitive element having a different resolving power depending on the direction in the field is oriented in the field due to the tilt angle of the thin plate glass with respect to the first optical path; A first imaging position related to a plane containing the same inclination angle and the optical axis in its own plane or a first group of planes parallel to this, which are imaging positions that occur differently depending on the angle of inclination, and the optical axis. a plane that is perpendicular to the first plane group or a second plane group that is parallel to the first plane group and includes in the own city.
With respect to the imaging position, the direction in which the resolving power of the photosensitive element is relatively high among the direction of the first group of planes or the direction of the second group of planes is (a) the direction of the first group of planes. (b) if it is relatively well along the direction of the second plane group, then the second imaging position; The device is characterized by comprising means for setting the relative posture and position of the thin plate glass and the photosensitive element so that the photosensitive element can be positioned.

[Example].

The present invention will be explained below with reference to illustrated embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before explaining the details of a photographing device showing one embodiment of the present invention, the concept of the present invention will be explained with reference to FIG.

FIG. 1 shows a schematic configuration of a single-lens reflex electronic still camera using a thin plate glass as a half mirror, which is a photographing device according to the present invention. The subject light incident from the ticking lens 29 having an optical axis of 0 has an angle θ
A part of the light is emitted as photographing light to a first optical path 0' on the exit side of the light, and the other part is branched to a second optical path A as finder light. The light flux of the first optical path is the light sensitive element COD
(Solid-state image sensor) An image is formed on the imaging surface of 8, while the second
The finder light in the optical path forms an image on the screen mat 12, and the image passes through the second mirror 18 to the finder section 20.
observed by. Note that the plane group α and β and the incident lights LA and L8 are as defined above. At the same time, the incident light LA.

The focus position for LB is the first imaging position P1.
and a second imaging position P2.

In the photographing device of the present invention, when the direction of high resolution in the horizontal or vertical scanning direction of the CCD 8 is more closely aligned with the direction of the first plane group α, the CCD 8 is positioned at the first imaging position P1. . Furthermore, if the second plane group β is more closely aligned with the direction of the second plane group β, the CC
Position D8. The relative posture and position of the shim plate glass 2 and the CCD 8, which position the CCD 8 as described above, are set by a drive means including a control means, a motor drive circuit, a drive motor, and an AF drive section. The photographing device of the present invention can be applied to zoom cameras as well as single-focus lens cameras. The driving means drives by the amount of relative movement corresponding to the imaging position P t =P 2 .

The photographing device of the present invention allows the CCD 8 to more effectively utilize its resolution ability by setting the imaging position as described above.

FIG. 2 shows a block configuration of a control section of a single-lens reflex electronic still camera showing an embodiment of the present invention. The control means 50 takes in object distance data from a distance measurement sensor for AF (automatic focusing) operation, drives an AF motor 53 via a motor drive circuit 52, and further controls a four-group focusing system using an AF drive section 34. Drives the focusing lens in the king lens section. Further, the output of the initial position sensor 54 is taken in and the focusing lens is reset to a predetermined reference position when the power is turned on or every time a photograph is taken. Further, the zooming position is detected by the zoom sensor 55, and the reference extension amount for focusing by zooming is corrected.

The E2FROM 56 stores the reference extension jl (corresponding to the neutral position) of the focusing lens relative to the subject distance, the correction value of the reference extension amount based on the zoom ratio, and the first. The offset value of the feed amount with respect to the second imaging position, etc. are stored, and the data is referred to by the control means 50 as necessary. The frame/field recording switch 5W57 is the frame/field recording mode for image data.
This is a switch that selects a field and instructs the control means 50 to switch the recording mode according to this mode designation. Focusing is performed to position the CCD 8 at the second imaging position.

Next, the configuration of the imaging optical system of the electronic still camera of this embodiment will be explained with reference to FIGS. 3 and 4.

The configuration of the imaging optical system of the camera includes a frame member and a block 1 that fixedly support the shin plate glass 2 by pressing it with a mirror holding plate 3 through cushioning materials 23a, 23b: 23c. , a ticking lens 29 , a CCD imaging optical system 27 , and a finder optical system 28 . And the above CC
The D imaging optical system 27 is fixed to the block 1 as described above.
Through the block 4 and the CCDg cam 5, the CCD
A CCD case 6 supported under tension by a spring 10 and a CCD 8 which is an image sensor disposed in the CCD case 6 with its imaging surface facing the optical axis O via an optical filter 7; CC for mounting on 6
It is constituted by a D presser plate 9.

Further, the finder optical system 28 is connected to the L block 1,
A mat receiver 11 attached by a pin screw 14 via a mat spring 15, a screen mat 12 having an imaging surface for a finder, a mat holder 13, and an F fixed to the L block 1 via the screen mat 12. block 17 and F block 1 in an oblique state on the finder optical axis A of the second optical path passing through the screen mat 12.
7, a second mirror 18 held by a mirror spring 19, a finder section 20 supported by the F block 17 in a state perpendicular to the optical axis A, an S block 21 fixed to the F block 17, and the light receiving surface of the finder section 20 supported by the F block 17. S facing optical axis A
The photometric sensor 22 is arranged in the block 21. The position and inclination of the mat holder 11 to which the mat holder is screwed is adjusted by means of an adjustment bin 16. Note that the imaging plane of the screen mat 12 is located at a relative position from the reflective surface of the thin plate glass 2 to the CCD.
It is set to be located at a position equivalent to the imaging position on g.

Furthermore, the ticking lens 29 has a four-group lens configuration, and as shown in FIG. A front cover 31 supported by the lens frame 30 via freely supported guide shafts 32a and 32b;
A focusing lens 33 (first group lens), which is one of the lens groups sequentially arranged along the optical axis 0, and an AF (automatic focus) drive unit 34 for the focusing lens 33.
and a variator lens 35 (second
group lens), a compensator lens 36 (third group lens), a zoom drive unit 37 that moves the variator lens 35 and compensator lens 36 according to zooming instructions, an aperture unit 38, and a relay lens 39 (
(4th group lens).

Note that the thin plate glass 2 is a thin plate (thickness 061 mm).
A reflective branching coating is applied to the front surface 2a having a predetermined flatness accuracy, and an anti-reflection coating is applied to the rear surface 2b. The shin plate glass 2 is attached to the L block 1 at an angle of 45'' with respect to the optical axis O, and the reflective coating surface of the shin plate glass 2 is brought into contact with the mirror support surface of the block 1, and the mirror holding plate is The shim plate glass 2 is fixed by screwing 3. In this way, the mirror 2 is supported obliquely at an angle of 45° with respect to the optical axis O.

To explain the working state of the light beam of the above-mentioned imaging optical system,
First, a part of the incident light from the ticking lens 29 passes through the thin plate glass 2 attached to the L block 1, so that the light enters a second optical path on its output side and approximately coaxial with the optical axis 0. The other part of the incident light is emitted onto the first optical path with the optical axis 0', and the other part of the incident light is directed perpendicularly to the incident optical axis O with a reflection angle corresponding to the incident angle on the reflective surface 2a of the thin plate glass 2. It is reflected and branched into a second optical path along axis A. The light beam emitted to the first optical path O' passes through the optical filter 7 and is projected onto the imaging surface of the CCD 8. On the other hand, the light beam reflected in the second optical path direction (optical axis A) forms an image on the imaging surface of the screen mat 12. The imaging light beam passes through the screen mat 12 and is reflected toward the finder section 20 by a second mirror 18 obliquely disposed on the front axis of the screen mat 12, and a portion of the transmitted light reaches the photometric sensor 22.

Next, regarding the imaging position (focus position) by the thin plate glass 2 in the imaging optical system, the α
The theoretical position difference δ between the focus position P1 due to A and the focus position P2 due to the β-merchant radiation LB is expressed as the thickness t of the thin plate glass 2, the inclination angle θ, and the refractive index n of the glass material.
(The refractive index of air is n.)

Figure 5 shows a vertical cross-section of the main parts of the thin plate glass 2 and the imaging section (
α plane) is shown, and this figure first shows the focus position P when the shin plate glass 2 is not present. α based on
A distance d1 from the heavy incident light LA to the focus position P1 is determined.

First, the incident light LA is divided into incident light parallel to the optical axis O and incident light inclined at an angle φ with respect to the optical axis O.

The former incident light is refracted by the shin plate glass 2, and the angle between the refracted light and the surface 2a of the shin plate glass 2 is θ'. The latter incident light is also refracted by the shin plate glass 2, and the angle between the refracted light and the surface 2a of the shin plate glass 2 is θ+φ+ε. After passing through the thin plate glass 2, the emitted light LA' forms an image on the position P1. Moreover, the luminous flux LA in the case where the shin plate glass 2 did not exist travels straight to the position P. image on top.

Furthermore, in the figure, if we consider the distances to the exit points of the incident light and refracted light parallel to the optical axis O, the distances Mc to the exit points of the incident light and refracted light that are inclined at an angle φ are shown as follows. That is, b-T 5in(θ'-θ) -old---
(1) C-TC(sin(φ+ε”j −cos(φ1ε) tanφ)・・・・・・・・・(2) Here, the distances TB and Tc are the thickness of the thin plate glass 2 of the refracted light, respectively. is the path length within, TB = t/s
It is expressed as 1nθ' Tc1llIt/51n (θ+φ+ε).

The above distance d is the position P. , Pl, from the triangle formed by the emitted light LA', dl--L-... (3) tanφ. Here, a is equal to the difference between the above distances and c from FIG. Therefore, by substituting the value of the difference between equations (1) and (2) into equation (3), and further substituting the above calculation equations for the distances To and Tc, we obtain [sin (φ+ε)−CO8( φ+ε). Furthermore, when this equation is modified to find d1, the ratio of ・tan φ)/l becomes (4).

On the other hand, regarding the angular relationship between the incident light LA and the refracted light, from the law of refraction, for the incident light parallel to the optical axis O, the angles θ and θ
Since the angle of incidence and the angle of refraction are 90''-〇 and 90'-θ', the relationship between cosθ'- and -cosθ
......(5). Also, for incident light tilted at an angle φ, the relationship between the angles (θ+φ) and (θ+φ+ε) is cos (θ+φ10g) mk* cos(θ+φ)...
...(6) becomes. However, k indicates the reciprocal of the relative refractive index of air and glass, and is the value of n 6 / n. Equations (5) and (8) become as follows. Then, if we set φ+ε-(θ+φ11ε)-θ and transform 5in(φ+ε) and cos(φ+ε), we get the following.

sin (φ+ri -5in(θ+φ10g) cosθ
-eos (θ+φ+ε)φs1nθ cos (φ+ ε) Snow cos (θ+φ+
ε) Cos θ+5in(θ+φ+ε)・Sln
θ Substituting this equation and the above equations (6) and (6°) into the above equation (7) can be obtained.

By substituting equations (5) and (5') into equation (4), we get
・・・・・・・・・(7) ・・・・・・・・・(8) are required.

Then, set 2CO52θ (θ+φ) in D San1- and 2cos'' (θ+φ) in E-1-, and further set Z in the parentheses of the third term of equation (8).Z
After finding and transforming, the paraxial solution of d1/l is therefore (9).

When the incident luminous flux LA is treated as paraxial light with respect to the optical axis O (φ-0), the value of dt/l is determined. First, since it is in equation (9), from equation (9) above, it becomes (10).

Also (8) From the formula ・・・・・・・・・(1,1) becomes.

Next, the above β when the thin plate glass 2 does not exist
Focus position P due to incident light on a plane.

Distance d2 (14th
(see figure).

First, as shown in FIG. 6, the incident light LB has an inclination angle φ with respect to the axis 0' parallel to the optical axis 0, the incident angle τ with respect to the surface of the shin plate glass 2, and the projected inclination of the shin plate glass 2. The conversion formula for determining the angle η is slnrmcos φ−sin θ −−−
---(12) cosτ' cos ηchick cosφ・c
os θ (13). Furthermore, the following relational expression can be obtained from these two expressions.

cosr-5in7 = sinφ −°−
(15) Also, according to the law of refraction, the angle of incidence of the incident light LB is 90°-τ, and if the angle that the refracted light makes with the thin plate glass 2 is τ', then the angle of refraction is 90°-τ' Therefore, the relationship between the angles τ and τ′ is CO8τ′鳳k co
sr......(17).

Further, when the refracted light is projected onto the surface of the thin plate glass 2, the angle η' it makes with the α plane becomes η' - η (18).

The angle φ' between the above refracted light and the optical axis O is determined by applying the relational expression (15) above to the refracted light, and further using (17) and (18).
, (1,3).

Transforming according to equation (16), sinφ'−cosτ'slnη'1111I
k@CO8τ·SInη −ksinφ (19). From equation (19), it can be seen that the ordinary law of refraction holds true for the apparent refraction of the incident light LB projected onto the β plane.

The angle θ' of the refracted light of the incident light LB projected onto the α plane with the thin plate glass 2 can be determined by applying equation (13) to the refracted light, and further (17), (19).

When rewritten according to equation ([5), it becomes. (20
) The relationship between θ' and θ in the equation indicates the apparent refraction of the incident light LB projected onto the α plane. And C in Figure 6
FIG. 7, which is a view in the direction of arrows, shows the state of refraction of the incident light LB projected onto the α plane. This is the projection distance on the β plane of the transmission distance t' of the refracted light of the incident light L8 within the thin plate glass 2. By substituting equation (20) into this equation and rearranging it, the ratio between the projection distance tB and the plate thickness t can be obtained.

From this equation, the paraxial solution for the paraxial ray with optical axis 0 is φ+0
On the other hand, according to the above equation (19), β of the refracted light of the incident light LB is
Since the projection onto a surface can be regarded as apparently normal refraction, it can be treated as refraction of a parallel flat glass plate with a thickness of 10. Then, a second imaging position P2 and an imaging position P where the shin plate glass 2 does not exist. positional deviation d2 with
(See Figure 8) is d2 tB (1-k) Divide both sides of this equation by t and further substitute (21), the ratio of positional deviation d2 and t is... (22) becomes.

Therefore, when the deviation amount δ of the imaging position regarding the paraxial light of the α commercial incident light LA and the β major incident light LB is determined as the ratio to the thickness t of the thin plate glass 2, it is obtained from equations (11) and (22). Become.

becomes.

Substituting specific numerical values, the refractive index of air n(1-1+
Glass refractive index n-1, 52, oblique angle θ-45'' of shim plate glass 2, and glass thickness t = 0.1
5 mm, the first and second imaging positions p1. The deviation δ of p2 is δ-35.3 μm.

Next, the results of actual measurements regarding the deviation δ in the imaging position described in 1.2 are shown in FIGS. 8 to 10 (A) and (B). 8th
The figure shows the case when the zoom ratio is standard, Fig. 9 shows the case when the zooming is tele, and Fig. 10 shows the case when the zooming is wide. (B) shows the change in MTF value for α-plane luminous flux (dotted line) and β-plane luminous flux (solid line) for each spatial frequency (10, 20, 30 ° 40 lines/m) with respect to the defocus amount in the state. It shows changes in each MTF value when the thin plate glass 2 is provided. Note that the position where the defocus amount is 0 in the figure simply indicates the reference position for measurement.

Since the peak point of the MTF value indicates the focus position, as shown in Figs. It is confirmed that there is a deviation of about 10 μm.

In the electronic still camera of this embodiment, the CCD 8 is aligned with the β plane along the higher resolution direction, for example, the horizontal direction (direction H in FIG. 1), and is focused at the second imaging position. Then, the control means 50 performs the AF operation. Further, when the direction in which the CCD 8 has a higher resolving power is the vertical direction (direction V in FIG. 1), the control means 50 causes the α plane along the vertical direction to correspond and to focus at the first imaging position. AF operation is performed by.

The data for the above-mentioned AF operation shall be stored in the E" FROM 56. That is, in the lens movement distance diagram with respect to the subject distance shown in FIG.
Data F for the neutral position of the imaging position of 1st . Movement position data F A corresponding to the second imaging position
, F n is stored as an offset amount with respect to the above F value. When setting the imaging position, the neutral position F and the above-mentioned offset amount are read out and focusing is performed. Note that if the focusing position changes due to zooming, the neutral position will naturally change, and the offset position will also change accordingly.

Frame/field recording switching 5W5 shown in FIG.
As mentioned above, 7 is a switch for switching the recording mode, and when this switching is performed, the direction of high resolution of the CCD 8 also changes depending on the selected recording mode. In general, field recording mode has higher resolution in the horizontal direction, and frame recording has higher resolution in the vertical direction. Therefore, focusing is performed by specifying either the offset amount for the upper Hi position data F A or F a in accordance with the direction indicating the high resolution that changes depending on the mode selection.

In the above embodiment, the direction of the second optical path is vertical, but the gist of the present invention can also be applied to a camera in which the thin plate glass 2 is installed obliquely in the horizontal direction as shown in FIG. Can be applied.

In the above embodiment, focusing is performed on the α or β plane, which has a direction that matches the direction of high resolution of the CCD 8. However, when considering the balance between the horizontal and vertical resolution of the imaging screen, In some cases, it may be effective to focus the image on a surface that is not along the direction, or rather on a surface that is not along that direction.

Further, although the above embodiment is an example applied to an AP operation camera, even if the focusing is manual focus, the focus ring is marked with the 1st and 2nd focus positions, and the C The present invention can also be applied through. Further, the present invention can also be applied to a power focus camera by specifying the focusing amount for the first and second imaging positions.

As a specific example of the direction of high response (high resolution) of the imaging system, in the case of a camera dedicated to field recording, the horizontal direction is the high response direction, and a camera that supports frame recording of approximately 300,000 pixels or less or 19 For high-definition televisions (HDTVs) and the like having less than about 10,000 pixels, the vertical direction is usually the direction of high response.

[Effects of the Invention] As described above, the photographing device using the thin plate glass for the half mirror of the present invention has the ability to reduce the resolving power of the photosensitive element against the shift in the imaging position caused by the oblique installation of the thin plate glass. By associating the higher direction of the image with the direction of the plane in which the deviation of the imaging position occurs, focusing is performed so that the photosensitive element is located at the corresponding imaging position.

According to the present invention, even if there is a difference in resolving power depending on the scanning direction of the photosensitive element, and even if there is a difference in the imaging position on the imaging optical system depending on the direction of the surface of the light beam, both directions can be selected. , it is possible to provide an imaging device that enables high-quality imaging without meaninglessly lowering the resolution of the photosensitive element.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of the present invention. FIG. 2 is a block diagram of the electrical equipment section of an electronic still camera showing an embodiment of the present invention. FIG. 3 is a schematic diagram of the electronic still camera shown in FIG. 2 above. FIG. 4 is an exploded perspective view of the imaging optical system and finder optical system of the image optical system; FIG. 4 is an exploded perspective view of the ticking lens section of the imaging optical system of the electronic still camera shown in FIG. 2; FIG. FIG. 6 is a perspective view of the main part of the shim plate glass portion of the imaging optical system shown in FIG. 3, and FIG. 7 ( A) is an enlarged longitudinal sectional view of the main part of the shim plate glass portion of the imaging optical system shown in FIG. 3 above, and FIG. Enlarged cross-sectional view, Figure 8 (A), Figure 9 (^), Figure 10 (^
) show the MTF characteristics of an electronic still camera that does not use thin plate glass, respectively. Figure 8 (^) is for the standard zoom ratio, Figure 9 (A) is for tele, and Figure 10 (A) is for wide. MTF characteristic diagram for Fig. 8 (B),
Figure 9 (B) and Figure 10 (B) respectively show the MTF characteristics of an electronic still camera using thin plate glass, with Figure 8 (B) showing the standard zoom ratio and Figure 9 (B)
is the MTF for tele, and Figure 10 (B) is for wide.
The characteristic diagram, FIG. 11, is a diagram showing the amount of lens movement with respect to the subject distance of the electronic still camera shown in FIG.
13 is a perspective view of a main part of an imaging optical system of an electronic still camera showing a modification of the above embodiment, FIG. 13 is a perspective view of a main part of a conventional photographing device, and FIG. FIG. 15 is a vertical cross-sectional view of the imaging optical system of the imaging device, and the MTF of the optical system of the imaging device shown in FIG.
It is a characteristic line diagram. 2...Shin plate glass 8...
...CCD (light sensitive element) 0...
Optical axis 0'...First optical path A...Second optical path θ...Inclination angle α. ......First plane α......First plane group β. ...Second plane β...Second plane group P1...αFocus position (first imaging position) of the major incident light P2... ...Focus position of 8-plane incident light (second imaging position)

Claims (3)

[Claims] (1) It is inserted into a predetermined imaging optical system at a predetermined inclination angle with respect to the optical axis of the imaging optical system, and a part of the incident light from the entrance side of the imaging optical system is inserted into the first optical path on the exit side of the imaging optical system. A photographing device employing a thin plate glass that emits the incident light and branches the other part of the incident light into a second optical path with a reflection angle corresponding to the incident angle of the incident light, the image capturing device employing a thin plate glass, which is dependent on the direction within the screen. light-sensitive elements having different resolving powers with respect to the first optical path, the same inclination angle being the imaging position that occurs differently depending on the direction in the screen due to the inclination angle of the thin plate glass. and a first imaging position related to a plane including the optical axis in its own plane or a first plane group parallel to this, and a first image forming position related to a plane including the optical axis in its own plane or perpendicular to the first plane group or a second plane parallel to this
A specific direction defined in relation to the resolving power of the photosensitive element among the first plane group or the second plane group is ) If it is relatively well along the first group of planes, the first image forming position is located; (b) If it is relatively well along the second group of planes, the second image forming position is An imaging device comprising: means for setting the relative posture and position of the thin plate glass and the photosensitive element so that the photosensitive element can be positioned at the image forming position. (2) A direction in which the photosensitive element has a relatively high resolution and the first or second plane group are arranged in relation to each other, and the photosensitive element is further positioned at the first or second imaging position. 2. The photographing device according to claim 1, wherein the photographing device can be (3) The photographing device is provided with a frame recording/field recording mode switching means, and the above-mentioned first method is provided in connection with the switching operation.
2. The photographing device according to claim 1, wherein the photosensitive element can be positioned at a second imaging position.