JP5369792B2 - Eyepiece magnification observation optical system, electronic viewfinder, and imaging device - Google Patents

Description

  The present invention relates to an eyepiece magnification observation optical system, an electronic viewfinder, and an imaging device used in an imaging device such as a still camera and a video camera that record digital images and moving images, and particularly, a necessary and sufficient viewing angle and image. The present invention relates to an eyepiece magnifying observation optical system, an electronic viewfinder, and an imaging apparatus that can shorten the overall length while maintaining performance and can reduce the manufacturing cost.

  2. Description of the Related Art Conventionally, two types of cameras, an optical viewfinder and an electronic viewfinder, are used. Of these, an electronic viewfinder is often used in digital imaging devices such as digital cameras and digital video cameras.

  An electronic viewfinder is an electric image signal output from an image sensor that is input to a display device such as a small liquid crystal to display an image, and the display is enlarged by an eyepiece magnification observation optical system and used as a viewfinder. Yes (see, for example, Patent Document 1).

  In order to improve portability in digital imaging devices, there is an increasing demand for smaller and thinner outer sizes, and eyepiece magnification observation optical systems for electronic viewfinders are also required to be small and thin. Yes.

  By the way, the electronic viewfinder has a function of adjusting the diopter so that the electronic viewfinder is in focus even with the naked eye according to the visual acuity of the user, that is, myopia, hyperopia, presbyopia and the like. This diopter adjustment is performed by moving at least one of a plurality of lens groups constituting the eyepiece magnification observation optical system in the optical axis direction. It is necessary to secure a certain distance between the eyepiece magnification observation optical systems, and there is a limit to thinning.

  The present invention has been made in view of the above problems, and can reduce the overall length while having a necessary and sufficient viewing angle and image performance, and can reduce the manufacturing cost. An object is to provide an electronic viewfinder and an imaging apparatus.

(1) In the present invention, a first lens group having negative refracting power and a second lens group having positive refracting power are arranged in order from the surface to be observed so as to be movable in the optical axis direction. An eyepiece magnification observation optical system having a positive refractive power, wherein the second lens group has two optical elements having a positive refractive power, and the radius of curvature, thickness, and refractive index of the two optical elements. And the optical characteristic values of the dispersion are the same, the surfaces of the two optical elements having the same shape face each other are arranged in the group, the focal length of the observation optical system is F, and the diopter of the observation image is L1 is the air distance from the observation surface to the front surface of the eyepiece magnification observation optical system when -1Dpt, and L2 is the distance from the observation surface when the diopter of the observation image is -1Dpt to the final surface of the eyepiece magnification observation optical system. when the most major to satisfy the following condition (1) and (2) And butterflies.
0.3 ≦ (L2−L1) /F≦0.5 (1)
0.6 ≦ L1 / F ≦ 0.9 (2)

  Further, although not particularly limited in the present invention, it is preferable that at least one of the optical elements constituting the first lens group and the second lens group has one aspheric surface.

  Although not particularly limited in the present invention, the optical element constituting the first lens group has an aspheric surface, and the aspheric surface has an absolute value of a radius of curvature as the distance from the optical axis increases within the effective beam diameter. An aspherical surface that is uniformly small is preferable.

  Although not particularly limited in the present invention, it is preferable that the two optical elements constituting the second lens group have aspherical surfaces having the same shape.

  Further, although not particularly limited in the present invention, it is preferable that the shapes of the outer edges of the effective beam diameter of the two optical elements are the same.

  Although not particularly limited in the present invention, the two optical elements are resin optical elements molded by an injection molding method, so that the positions of the gates at the time of molding do not coincide with each other when viewed from the optical axis direction. It is preferable that the two lens groups are disposed.

  (2) The present invention is also an electronic viewfinder for observing an image displayed on a display element by an electrical image signal using an eyepiece magnification observation optical system, wherein the eyepiece magnification observation optical system is defined in claim 1. 8. An eyepiece magnification observation optical system according to any one of 1 to 7.

  (3) The present invention is also an imaging apparatus having the above-described electronic viewfinder.

  According to the present invention, there are provided an eyepiece magnification observation optical system, an electronic viewfinder, and an imaging apparatus that can shorten the overall length while having a necessary and sufficient viewing angle and image performance, and that can reduce the manufacturing cost. be able to.

It is an optical arrangement | positioning figure which shows 1st Example of the eyepiece expansion observation optical system of this invention. It is an aberration curve figure of the above-mentioned eyepiece magnification observation optical system. It is an optical arrangement | positioning figure which shows 2nd Example of the eyepiece expansion observation optical system of this invention. FIG. 6 is an aberration diagram of the eyepiece magnification observation optical system. It is an optical arrangement | positioning figure which shows 3rd Example of the eyepiece expansion observation optical system of this invention. FIG. 6 is an aberration diagram of the eyepiece magnification observation optical system. It is an optical arrangement | positioning figure which shows 4th Example of the eyepiece expansion observation optical system of this invention. FIG. 6 is an aberration diagram of the eyepiece magnification observation optical system. It is an optical arrangement | positioning figure which shows 5th Example of the eyepiece expansion observation optical system of this invention. FIG. 6 is an aberration diagram of the eyepiece magnification observation optical system. It is an optical arrangement | positioning figure which shows 6th Example of the eyepiece expansion observation optical system of this invention. FIG. 6 is an aberration diagram of the eyepiece magnification observation optical system. It is a back perspective view which shows the Example of the electronic viewfinder based on this invention. It is a front perspective view of the said Example. It is a front perspective view which shows the example of a digital camera as an Example of the imaging device which concerns on this invention.

  Embodiments of an eyepiece magnification observation optical system, an electronic viewfinder, and an imaging apparatus according to the present invention will be described below with reference to the drawings.

<Ocular magnification observation optical system>
Hereinafter, first to sixth examples of the eyepiece magnification observation optical system according to the present invention will be described. In the optical layout diagram showing each example, the surface indicated by the bold line is an aspherical surface.

Hereinafter, the eyepiece magnification observation optical system according to the first example will be described with reference to FIGS. 1 and 2.
An eyepiece magnification observation optical system 1 according to the present embodiment is an optical system for a user to enlarge and view a display element 2 that is a small liquid crystal screen, as shown in FIG. The corresponding optical element 3 and the second lens group 4 are configured.

  The optical element 3 has a negative refractive power because the first surface 31 facing the display element 2 is an aspherical surface. This aspherical surface is an aspherical surface in which the absolute value of the radius of curvature decreases uniformly with distance from the optical axis within the range of the effective beam diameter.

  In the second lens group 4, two optical elements 5 and 6 having the same shape and having a positive refractive power are arranged to face each other. The first optical element 5 has a first surface 51 aspherical, and the second optical element 6 has a second surface 62 aspherical. The shape of the edge portion outside the effective beam diameter of the two optical elements 5 and 6 is the same. These two optical elements 5 and 6 are resin optical elements molded by an injection molding method, and are arranged in the eyepiece magnification observation optical system 1 so that the sprue at the time of molding does not overlap when viewed from the optical axis direction. Has been.

  In the present embodiment, the diopter is adjusted by moving the eyepiece magnification observation optical system 1 together in the optical axis direction.

“1” on each surface from the display element surface, the optical element 3 constituting the first lens group, the optical element 5 of the second lens group, the optical element 6 of the second lens group, and the pupil of the user in the above embodiment. To “8” in order. In the above embodiment, the surface numbers “2”, “4”, and “7” are aspherical surfaces. For these surfaces, Table 1 shows specific numerical values when the radius of each surface is R, the thickness or distance between each surface is D, the refractive index of each optical element, that is, the lens is Nd, and the dispersion rate is Vd. Show.
Table 1

Table 2 shows the aspherical coefficients when the estimated number of circles is K and Ai is an i-th aspherical surface.
Table 2

  According to the eyepiece magnification observation optical system of the present embodiment, correction of chromatic aberration is performed between the optical element 3 having the negative refractive power of the optical element 3 and the optical element 5 of the second lens group 4. As shown in the aberration diagram, both axial chromatic aberration and lateral chromatic aberration are in a good correction state. Further, a total of three surfaces including the first surface 31 of the optical element 3, the first surface 51 of the optical element 5 of the second lens group 4, and the second surface 62 of the optical element 6 of the second lens group 4 are aspherical surfaces. By doing so, the flatness of the image is secured while suppressing distortion.

  In addition, by constructing the second lens group with two optical elements having positive refractive power, it is possible to shorten the focal length of the entire system without increasing spherical aberration and obtain the required apparent viewing angle. It becomes.

  In addition, by making the optical characteristic values of the two optical elements constituting the second lens group the same design, the manufacturing cost can be kept low.

  Further, by arranging the optical elements 5 and 6 constituting the second lens group 4 in the same group so that the same surface shape sides are opposed to each other, the height of the light beam passing through each surface from the optical axis is increased. Since it can be made substantially the same between the case where it is arranged on the display element side in the second lens group and the case where it is arranged on the pupil side, it becomes easy to design an outer shape of the same shape.

  Further, at least one surface of the optical element constituting the first lens group is an aspherical surface, and the aspherical surface is an aspherical surface in which the absolute value of the radius of curvature is uniformly reduced as the distance from the optical axis is within the effective beam diameter range. Therefore, it is possible to efficiently correct curvature aberration, curvature of the image surface, and astigmatism.

  Moreover, since the shape of the edge part outside the optical axis effective diameter of the two optical elements constituting the second lens group is the same, the two optical elements constituting the second lens group are components manufactured from one drawing. It can be used, and manufacturing costs and component management costs can be reduced.

  In addition, since the two optical elements constituting the second lens group are resin optical elements molded by an injection molding method and are assembled and arranged in the group so that the gates at the time of molding do not coincide, It becomes possible to mold the two optical elements in the lens group with the same mold. Thereby, manufacturing cost can be reduced. Also, because the pouring gate direction is changed, non-rotationally symmetric surface shape errors that occur during molding, and non-uniformities such as the refractive index and sub-refraction inside the resin overlap on the same optical axis, resulting in image degradation. It is possible to prevent duplication, prevent local deterioration of image performance, and obtain an eyepiece magnification observation optical system with stable quality.

  According to this embodiment, the display element diagonal length is 9.4 mm, the apparent viewing angle is about 24 degrees, and a sufficient viewing angle is obtained. It is possible to obtain an eyepiece magnification optical system at a low cost.

  The eyepiece magnification observation optical system according to the second example will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the eyepiece expansion observation optical system which concerns on 1st Example.

  The eyepiece magnification observation optical system 1 according to the present embodiment shown in FIG. 3 is an optical system for the user to enlarge and view the display element 2 that is a small liquid crystal screen, as in the first embodiment. An optical element 3 constituting the first lens group and a second lens group 4 are included. Unlike the first lens group in the eyepiece magnification observation optical system according to the first example, the optical element 3 is an optical element composed of only a spherical surface and has a negative refractive power.

  Similarly to the second lens group in the eyepiece magnification observation optical system according to the first example, the second lens group 4 includes first and second optical elements 5 and 6 made of the same resin having positive refractive power. It is arranged to face each other. The first surface 51 of the optical element 5 is an aspheric surface, and the second surface 62 of the optical element 6 is an aspheric surface. Thus, since the optical elements 4 and 5 of the 2nd lens group 4 are the same shapes, these can be produced with the same metal mold | die and manufacturing cost can be held down low.

  Unlike Example 1, in the eyepiece magnification observation optical system of this example, the optical element 3 is composed only of a spherical surface, and the viewing angle is 24.5 degrees with respect to the diagonal length of the display element of 9.4 mm. . Although the refractive power of the entire system is almost the same as that of the first embodiment, the refractive powers of the first lens group and the second lens group are weakened to reduce the thickness in the optical axis direction.

Similarly to the first embodiment described above, in this embodiment as well, numbers are assigned in order from “1” to “8” on each surface. In this embodiment, the surface numbers “4” and “7” are aspherical surfaces. For these surfaces, as in Table 1 described in the first embodiment, the radius of each surface is R, the thickness or distance between each surface is D, the refractive index of each optical element or lens is Nd, and the dispersion is Table 3 shows specific numerical values when the rate is Vd.
Table 3

Table 4 shows the aspheric coefficients when the estimated number of circles is K and Ai is an i-th aspheric surface.
Table 4

  Since these lens groups have positive refractive power as a whole, the space required for movement of each lens group is displayed during diopter correction while shortening the overall length of the eyepiece optical system. It is ensured between the element 2.

  As a result, as shown in the aberration diagram of FIG. 4, the correction of chromatic aberration of magnification is inferior to that of the eyepiece magnification observation optical system according to Example 1, but is corrected to a range that is not problematic in practice. Other effects are the same as those of the first example except for the effect of making the first lens group an aspherical surface.

  The eyepiece magnification observation optical system according to the third example will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the eyepiece expansion observation optical system which concerns on 1st Example.

  The eyepiece magnification observation optical system 1 according to the present embodiment is also an example in which the optical element 3 is configured by only a spherical surface, as in the eyepiece magnification observation optical system according to the second embodiment.

  An eyepiece magnification observation optical system 1 according to the present example shown in FIG. 5 is an optical system for a user to enlarge and view the display element 2 that is a small liquid crystal screen, as in the first embodiment. An optical element 3 constituting the first lens group and a second lens group 4 are included.

Similarly to the first embodiment described above, in this embodiment as well, numbers are assigned in order from “1” to “8” on each surface. In this embodiment, the surface numbers “4” and “7” are aspherical surfaces. For these surfaces, as in Table 1 described in the first embodiment, the radius of the surface is R, the thickness or distance between the surfaces is D, the refractive index of each optical element, that is, the lens is Nd, and the dispersion is Table 5 shows specific numerical values when the rate is Vd.
Table 5

Table 6 shows the aspheric coefficients when the estimated number of circles is K and Ai is an i-th aspheric surface.
Table 6

  In this embodiment, since the arrangement of refractive powers of the optical element 3 and the second lens group 4 constituting the first lens group is substantially the same as that of the first embodiment, as shown in the aberration diagram of FIG. Is fully corrected. Other effects are the same as in the second embodiment.

  The eyepiece magnification observation optical system according to the fourth example will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the eyepiece expansion observation optical system which concerns on 1st Example. This embodiment is an example in which the refractive power of each lens group is further reduced in the configuration of the second embodiment.

Similarly to the first embodiment described above, in this embodiment as well, numbers are assigned in order from “1” to “8” on each surface. In this embodiment, the surface numbers “4” and “7” are aspherical surfaces. For these surfaces, as in Table 1 described in the first embodiment, the radius of the surface is R, the thickness or distance between the surfaces is D, the refractive index of each optical element, that is, the lens is Nd, and the dispersion is Table 7 shows specific numerical values when the rate is Vd.
Table 7

Table 8 shows the aspherical coefficients when the estimated number of circles is K and Ai is an i-th aspherical surface.
Table 8

  Compared with Examples 1 to 3, the thickness of the optical system in the optical axis direction is small, but the total length at -1 Dpt is long. Further, as shown in the aberration diagram of FIG. 8, the chromatic aberration of magnification also increases. Other effects are the same as those of the second and third embodiments.

  An eyepiece magnification observation optical system according to the fifth example will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the eyepiece expansion observation optical system which concerns on 1st Example. In this embodiment, the aspherical surface in the second lens group 4 is eliminated from the configuration of the first embodiment, and the aspherical surface is used only for the optical element 3.

Similarly to the first embodiment described above, in this embodiment as well, numbers are assigned in order from “1” to “8” on each surface. In this embodiment, only the surface number “2” is an aspherical surface. For these surfaces, as in Table 1 described in the first embodiment, the radius of the surface is R, the thickness or distance between the surfaces is D, the refractive index of each optical element, that is, the lens is Nd, and the dispersion is Table 9 shows specific numerical values when the rate is Vd.
Table 9

Table 10 shows the aspheric coefficients when the estimated number of circles is K and Ai is an i-th aspheric surface.
Table 10

  According to the eyepiece magnification observation optical system 1 of this embodiment, as shown in the aberration diagram of FIG. 10, the flatness of the image plane is slightly inferior to that of the first embodiment, but other aberration correction conditions are the same. This embodiment is a suitable example when it is desired to reduce the cost for manufacturing the aspherical surface of the second lens group 4. The other effects are the same as those of the first embodiment except for the effects obtained by providing the two optical elements constituting the second lens group with aspheric surfaces.

  An eyepiece magnification observation optical system according to the sixth example will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the same structure as the eyepiece expansion observation optical system which concerns on 1st Example.

  In this embodiment, the optical element 3 and the optical element 5 on the display element 2 side of the second lens group 4 are joined, and the aspherical surface is the first surface 31 of the optical element 3, The second surface 52 of the optical element 5 of the second lens group 4 and the first surface 61 of the optical element 6 of the second lens group 4 are provided.

Similarly to the first embodiment described above, in this embodiment as well, numbers are assigned in order from “1” to “8” on each surface. In this embodiment, the surface numbers “2”, “5”, and “6” are aspherical surfaces. For these surfaces, as in Table 1 described in the first embodiment, the radius of the surface is R, the thickness or distance between the surfaces is D, the refractive index of each optical element, that is, the lens is Nd, and the dispersion is Table 11 shows specific numerical values when the rate is Vd.
Table 11

Table 12 shows the aspheric coefficients when the estimated number of circles is K and Ai is an i-th aspheric surface.
Table 12

  In the eyepiece magnification observation optical system of the present embodiment, as shown in the aberration diagram of FIG. 12, the correction status of each aberration is almost the same as that of the fifth embodiment and is good.

  In this embodiment, since the air gap between the optical element 3 and the second lens group 4 having high sensitivity to image performance is eliminated by bonding, there is an increase in cost associated with the bonding operation, but stable image performance is achieved. It can be easily realized. In addition, since the interface of the optical system in contact with air is reduced, it is possible to prevent a decrease in image contrast due to internal reflection, and to reduce the phenomenon in which the reflection of the pupil is visible to the observer. Therefore, this is a suitable example when importance is attached to optical quality including stability of performance at the time of mass production and characteristics other than aberration. Other effects are the same as in the first embodiment.

The variable intervals of the eyepiece magnification observation optical systems in the first to sixth examples are compared. Table 13 shows the distance (D1) between the first surface (the surface of the display element 2) and the second surface (the first surface 51 of the optical element 3) in each example, the image diopter is −5 Dpt, − This is calculated for each of 1Dpt and + 3Dpt.
Table 13

The eyepiece magnification observation optical systems in the first to sixth examples all satisfy the following conditional expressions.
0.3 ≦ (L2−L1) /F≦0.5 (1)
0.6 ≦ L1 / F ≦ 0.9 (2)
However, when the focal length of the eyepiece magnification observation optical system is F, the diopter of the observation image is −1 Dpt, the air interval from the observation surface to the forefront of the eyepiece magnification observation optical system is L1, and the diopter of the observation image is −1 Dpt. Let L2 be the distance from the observation surface to the final surface of the eyepiece magnification observation optical system. Table 14 shows the values of the conditional expressions in each of the above examples in this case.
Table 14

  Since the eyepiece magnification observation optical systems in the first to sixth examples satisfy the conditional expressions (1) and (2), the entire length of the optical system can be kept short and the viewing angle can be increased. In addition, it is possible to ensure the amount of movement required when the distance from the display element is appropriately set and the diopter is adjusted in the minus direction.

If the upper limit of the range of conditional expression (1) is exceeded, the thickness of the entire optical system group in the optical axis direction becomes excessive, and it becomes difficult to secure a moving amount for adjusting the diopter on the plus side. Below the lower limit of the range of conditional expression (1), it becomes difficult to obtain the required apparent viewing angle due to the excessive focal length.

  If the upper limit of the range of the conditional expression (2) is exceeded, the negative refractive power of the first lens group will be insufficient, and the correction of chromatic aberration will be hindered. If the lower limit of the range of the conditional expression (2) is not reached, the distance between the display element and the optical system becomes insufficient, and it becomes impossible to secure a moving amount for diopter correction on the minus side. Will not hold.

<Electronic viewfinder>
An electronic viewfinder according to an embodiment of the present invention will be described with reference to FIGS. 13 and 14.

  An electronic viewfinder 10 according to the present embodiment includes an eyepiece magnification observation optical system 1, a diopter adjustment dial 7, and an attachment portion 8 to the camera body. Further, a display element that displays an image by an electrical image signal is built in, and an image displayed on the display element is observed by the eyepiece magnification observation optical system 1. On the camera body side, the subject image formed by the photographing lens is converted into an image signal by the image sensor. By inputting the image signal on the camera body side to the display element of the electronic viewfinder 10, the subject image is displayed on the display element.

  The eyepiece magnification observation optical system 1 is the same as any one of Examples 1 to 6 described in the embodiment of the eyepiece magnification observation optical system according to the present invention.

  The diopter adjustment dial 7 is a dial for adjusting the diopter of the electronic viewfinder 1. When the user turns the diopter adjustment dial 7, each lens group of the internal eyepiece magnification observation optical system 1 moves in parallel to the optical axis direction. Thereby, the diopter of the electronic viewfinder 10 can be optimized for each user.

  The attachment portion 8 is a configuration for attaching the electronic viewfinder 10 to a camera body (not shown), and is formed by digging a groove in the lower portion of the electronic viewfinder 10. The electronic viewfinder 10 is attached to the camera body by fitting this groove with a ridge provided in the upper part of the camera body.

  According to the electronic viewfinder 10 according to the present embodiment, a space necessary for the movement of each lens group during diopter correction is secured between the display element 2 and the total length of the eyepiece optical system is shortened. Therefore, the electronic viewfinder 10 can be downsized and the manufacturing cost can be kept low.

<Imaging device>
An embodiment of an imaging apparatus according to the present invention will be described using a digital camera as an example with reference to FIG.

  The digital camera according to the present embodiment is configured by attaching an electronic viewfinder 10 to a camera body 20 including a power button 21, a shutter button 22, and an imaging optical system 23.

  The power button 21 is provided on the upper part of the camera body 20 and is a button for turning on / off the power of the camera body 20.

  The shutter button 22 is a button for taking a picture when the camera body 20 is turned on. When the user presses the shutter button 22, a photographing operation by the camera body 20 is performed.

  The imaging optical system 23 includes a lens barrel that holds a plurality of lens groups therein. The lens barrel can be moved back and forth in the optical axis direction, and focusing is performed by moving at least a part of the plurality of lens groups in the optical axis direction in accordance with the movement of the lens barrel.

  The electronic viewfinder 10 is the same as the electronic viewfinder 10 described in the embodiment of the electronic viewfinder.

  According to the digital camera according to the present embodiment, since the electronic viewfinder 10 that has been reduced in size is attached, the attachment part on the camera body 20 side can be reduced in size. Therefore, the camera body 10 can be reduced in size, and a digital camera with excellent portability and low manufacturing costs can be obtained.

DESCRIPTION OF SYMBOLS 1 Eyepiece magnification observation optical system 2 Display element 3 Optical element 31 1st surface 32 2nd surface 4 2nd lens group 5 Optical element
51 1st page
52 2nd surface 6 Optical element
61 1st page
62 Second surface 7 Diopter adjustment dial 8 Mounting portion 10 Electronic viewfinder 20 Camera body 21 Power button 22 Shutter button 23 Shooting optical system

JP 2003-204455 A

Claims (8)

A first lens group having negative refracting power and a second lens group having positive refracting power are arranged so as to be movable in the direction of the optical axis and have positive refracting power as a whole. An eyepiece magnification observation optical system,
The second lens group includes two optical elements having positive refractive power,
The optical characteristic values of the radius of curvature, thickness, refractive index and dispersion of the two optical elements are the same, respectively.
The two optical elements are arranged in a group with the same surface facing each other ,
When the focal length of the observation optical system is F, the air interval from the observation surface when the observation image has a diopter of -1 Dpt to the forefront of the eyepiece magnification observation optical system is L1, and the diopter of the observation image is -1 Dpt An eyepiece magnification observation optical system that satisfies the following conditional expressions (1) and (2) when the distance from the observation surface to the final surface of the eyepiece magnification observation optical system is L2 .
0.3 ≦ (L2−L1) /F≦0.5 (1)
0.6 ≦ L1 / F ≦ 0.9 (2) Eyepiece magnification observation optical system of claim 1, wherein one surface for at least one is an aspheric surface of the optical element constituting the first lens group and the second lens group. Having the optical element is aspherical constituting the first lens group, the aspherical surface according to claim 2 absolute value of the radius of curvature with distance from the optical axis in the range of effective aperture is aspherical reduced uniformly The eyepiece magnification observation optical system described. The eyepiece magnification observation optical system according to claim 2 or 3, wherein the two optical elements constituting the second lens group each have an aspheric surface having the same shape. The eyepiece magnifying observation optical system according to any one of claims 1 to 4 , wherein the shape of the outer edge portion of the light beam effective diameter of the two optical elements is the same. The two optical elements are resin optical elements molded by an injection molding method, and are arranged in the second lens group so that the positions of the pouring gates at the time of molding do not coincide when viewed from the optical axis direction. The eyepiece magnification observation optical system according to any one of 1 to 5 . An electronic viewfinder for observing an image displayed on a display element by an electrical image signal using an eyepiece magnification observation optical system, wherein the eyepiece magnification observation optical system is according to any one of claims 1 to 6 . Electronic viewfinder, an eyepiece magnification observation optical system. An imaging apparatus having the electronic viewfinder according to claim 7 .

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