JPH03212630A - Photographing device - Google Patents

Abstract

PURPOSE:To always obtain accurate autofocusing by correcting the difference of optical path length between in the case of focus detection and in the case of photographing exposure in every finder unit in a camera in which plural kinds of finder units are interchangeable. CONSTITUTION:A camera main body 1 incorporates a film feeding mechanism, a shutter mechanism, a focus detection device 1-14 and a sub mirror 1-15 for making a luminous flux incident on the device 1-14. The finder unit which can be freely attached to and detached from the main body 1 incorporates a finder optical system and a photometry means and has three types. They are the finder optical system of a single-lens reflex type, the types 2 and 2' incorporating a main mirror 2-12 or a translucent main mirror 2-12', and the type 3 incorporating the optical system of a twin lens reflex type. The CPU of the main body 1 has the subroutine of the correction operation of the optical path length, and the difference of the optical path length between in the case of the focus detection and in the case of the exposure of a photographing optical system is arithmetically operated and corrected in accordance with the type of the mounted finder unit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a camera system, that is, a photographing device consisting of a plurality of components, and more specifically, to a camera having a structure in which a plurality of types of finder units can be attached. The present invention relates to a variable type photographing device consisting of a combination of a main body and the finder unit.

[Prior Art] Conventional portable cameras can be broadly classified into interchangeable lens cameras and non-interchangeable lens cameras, depending on whether lenses can be replaced or not.

A typical single-lens reflex camera is a single-lens reflex camera with interchangeable lenses, and a known single-lens reflex camera consists of a camera body that has a film feeding mechanism, a shutter mechanism, and a finder optical system, and a photographic optical system and an aperture. It consists of a built-in mechanism and an interchangeable lens that can be freely attached to and detached from the camera body.

Generally, at least three or more interchangeable lenses are prepared to be attached to the camera body, and many accessories are also prepared to be attached to the interchangeable lenses and the camera body. A camera system is composed of a lens and other attached devices.

Therefore, almost any situation can be photographed with a single-lens reflex camera, and many wonderful photographs have been taken with a single-lens reflex camera.

On the other hand, cameras with non-interchangeable lenses were developed specifically for snapshot photography by people who are not familiar with camera operation techniques, and are widely used in Japan under the general name of compact cameras. This type of camera only allows for interchangeable lenses, and is designed to be lightweight and inexpensive, so it is difficult to take pictures with the kind of skill that is normally taken with a single-lens reflex camera. It has the great advantage of being portable.

Therefore, the two known types of cameras mentioned above have conventionally been used depending on the purpose and usage situation. For example, a compact camera is used when you want to reduce the weight and volume of your carry-on baggage as much as possible without worrying about the quality of the photos; BACKGROUND ART Single-lens reflex cameras have been used to take highly accurate and accurate photographs, or to photograph distant objects at high magnification. In order to use different cameras depending on the purpose of photography, camera users often carry the two types of cameras with them when they go out to take pictures.

[Problems to be solved by the invention] However, it is unavoidable that the problem of having to carry two cameras increases the amount of luggage, and also, since two cameras have to be purchased, There was a problem that the purchase cost was high.

Therefore, in consideration of the above-mentioned current situation, the present applicant has proposed a variable type photographing device (variable type camera) with a replaceable finder configured so that multiple types of finder units can be selectively attached to a single camera body. system).

When planning a photographic device with an interchangeable viewfinder as described above, it is an important issue to decide which part of the camera should incorporate what kind of mechanism. As a result of various studies, the inventors of the present invention have developed a camera body that incorporates a film feeding mechanism and a shutter mechanism, as well as a focus detection device and a sub-mirror for making light beam incident on the focus detection device, a finder optical system and The above-mentioned variable type photographing device with replaceable finder is configured by at least two types of finder units which have built-in photometry means and are configured to be detachably attached to the camera body. This variable type photographing device includes the following three types (three types) of finder units that can be alternately attached to the camera body.

The finder unit of the first type has a built-in finder optical system and main mirror that have almost the same configuration as the conventional no-eye reflex type (hereinafter referred to as the milk R type), and the finder unit cannot be replaced. SL configured to be put into use by attaching a lens
This is an R-type finder unit. The second type of finder unit has a built-in finder optical system similar to that of a conventional SLR camera, as well as a semi-transparent main mirror, and the finder unit can also be used by attaching an interchangeable lens. SL provided
This is an R-type finder unit. The third type of finder unit differs from the first and second types of finder units in that it incorporates a photographic optical system and a finder optical system independent of the photographic optical system.

Three different types of cameras are constructed by attaching the three different types of finder units as described above to the camera body, but these three types of cameras differ in their optical system configuration, mirror operation, etc. Since these are different from each other, focus adjustment control corresponding to the optical system configuration, mirror operation, etc. of each type of camera is required during distance measurement and autofocusing.

An object of the present invention is to provide a variable type photographing apparatus having an replaceable finder as described above, which is equipped with a control means capable of performing focusing control corresponding to the configuration of the optical system of each type of photographing apparatus. That's true.

[Means for Solving the Problems] The photographing device of the present invention includes a control means for changing the amount of focus adjustment according to the type of finder unit attached to the camera body. Accurate autofocusing is always possible no matter which finder unit is attached.

[Implementation example] The present invention will be described in detail below with reference to the drawings.

FIG. 9 is a perspective view showing an example of the components of the photographing device of the present invention. The device of the present invention, as shown in FIG.
Only one camera body 1, single-lens reflex type (hereinafter referred to as breast R type) finder units 2 and 2° that can be detachably attached to the camera body 1, and finder units 2 and 2° that can be detachably attached to the camera body 1. It is comprised of a range finder type (hereinafter referred to as RF type) finder unit 3 that can be freely attached.

When the finder unit 2 or 2 is attached to the camera body 1, the finder unit 2 or 2 is also attached.
By attaching the interchangeable lens 4 to
When an LR type camera is configured and the finder unit 3 is attached to the camera body 1, it becomes a lightweight camera similar to a conventional compact camera (that is, the finder optical system is independent from the photographing optical system, and the lens cannot be replaced). camera) is configured.

The structures of the camera body 1, finder units 2, 2' and 3, and interchangeable lens 4 will be explained below with reference to FIGS. 9 to 18.

Mechanical fishing bridge of camera body 1 At the center of camera body 1 are finder units 2 and 2'' and rear portions 2-1 and 2''-1 of 3, respectively.
In addition, a space for fitting the cartridge 3-1 is formed, and as shown in FIG.
-1 and a spool chamber 1-2 are arranged. At the rear of the space, a main body frame 1-4 with a built-in focal brain shutter 1-3 is arranged at a position sandwiched between the patrone chamber 1-1 and the spool chamber 1-2. An aperture 1-5 is formed immediately after the shutter 1-3. Further, film guide rails 1-6 for guiding the film are formed on the outside of the aperture in the camera body frame, parallel to both upper and lower sides thereof.

The cartridge chamber 1-1 has a known rewinding fork 1-7.
protrudes so that it can move forward and backward. A known spool 1-8 is arranged in the spool chamber 1-2, and a motor 1-9 is accommodated in the spool 1-8.

A power transmission mechanism 1-10 for transmitting the power of the motor 19 to the fork 1-7, the spool 1-8, the shutter mechanism, and a movable sub-mirror to be described later is housed within the camera body located below the space. ing.

In addition, 2-11 is a publicly known shutter release button, 1
-12 is a dial type operation member, and 2-13 is a groove for fitting the respective eyepiece portions of finder units 2, 2°, and 3, which will be described later.

said space (i.e. finder unit 2 and 2°
A focus detection device 1-14 for autofocus is built in the bottom portion of the space (space for fitting the rear portions of 3 and 3), and the focus detection device 1-14
A sub-mirror 1-15 for making a light beam incident on the space is arranged within the space. The submirror 1-15 is attached to a submirror support plate 1-30, and the submirror support plate 1-30 can be raised up by a mechanism not shown.

An arcuate groove 1-18 is provided through one side wall surface of the space, and a main mirror drive lever 1-19 that moves within the groove projects into the space. The main mirror drive lever 1-19 is adapted to engage with a main mirror drive member within the finder unit 2 when the finder unit 2 is attached to the camera body 1.

front end surfaces 1-20 and 1-2 of the two side wall portions of the space;
1 is the abutting surface of the finder units 2, 2'' and 3, and the front end surface 1-20 of one side wall section has electrical connections between the finder units 2.2°, 3 and the camera body 1. Connections (for data and signal transmission)
A contact group 1-22 for connecting the finder unit is provided protrudingly. Also, the front end surface 1-2 of the other side wall portion
1 is a finder unit attachment detection switch (this switch is for electrically detecting that the finder units 2, 2" and 3 are attached to the camera body 1, and is provided in the camera body 1. The movable pin 1-23 of the main body 1-23 is protruded.

Each front plate portion 2-2 of the finder unit 2.2°, 3 abuts against the surfaces 1-20 and 1-21.
．． A contact group for connecting the camera body corresponding to the finder unit connecting contact group 1-22 is provided on the rear surface of the finder unit 2'-2, 3-2.
2" and 3 are attached to the camera body 1, the finder unit connection contact group 1-22 contacts the camera body connection contact groups of finder units 2 and 3, and the camera body 1 and finder units 2, 2', 3 are connected. An electrical connection is made between the

As shown in FIG. 11, the finder unit connecting contact group 1-22 is a pin-shaped movable terminal that is always urged forward by a spring 1-24, and is connected to each of the finder units 2, 2°, and 3. Non-movable camera body connection contact groups 2-19, 2°-19 and 3-1 provided in
8 (see FIG. 17) by the force of spring 1-24.

An arc-shaped vertical surface 1-25 is formed at the front end of the bottom portion of the space, and is in contact with the rear end surface of the interchangeable lens 4. electrical connections (connections for data and signal transmission)
A lens connection contact group 1-26 is protruded. This lens connection contact group 1-26 has the same structure as the finder unit connection contact group 1-22 described above, and as shown in FIG. 12, the pin is always biased forward by a spring 1-27. It is a movable terminal.

Therefore, when the interchangeable lens 4 is attached to the finder unit 2 or 2° and the finder unit 2 or 2° is attached to the camera body 1 as shown in FIG. Contact group 4-
1 and the lens connecting contact group 1-26 of the camera body 1 are pressed into contact with each other by the force of the spring 1-27, and as a result, the camera body 1 and the interchangeable lens 4 are electrically connected to each other.

Outside the arrangement position of the lens connection contact group 1-26 of the camera body 1, there is a pair of mounting pin insertion holes 1-2 for inserting mounting pins protruding from the finder units 2, 2° and 3, which will be described later. 28 is open toward the front.

A recess 1-29 on the front surface of the camera body housing the cartridge chamber 1-1 is fitted with a finder unit 2 and a lock release button support piece for attaching and detaching an interchangeable lens, which will be described later and is protruded at 2°. is formed.

Finder unit 2 and 2° structure Finder units 2 and 2' are units for constructing an SLR type camera, and both have almost the same structure, but as explained later, finder unit 2 is a movable type. The finder unit 2' is different in that it has a built-in main mirror, and the finder unit 2' has a fixed main mirror (that is, it does not move away from the photographic optical axis during exposure). Below, partial structures common to both will be explained at the same time, and partial structures and constituent members of the finder unit 2' will be indicated in parentheses.

The finder units 2 and 2' have a rear portion 2-1 configured to be fitted into the space of the camera body 1.
(2'-1), and a front plate portion 2-2 (2'-2) constituting a part of the front plate of the camera body 1.
The top plate portion 2- which is integrated with the rear portion 2-1 (2°-1)
3 (2'-3).

A mount 2-4 (2'-4) for mounting an interchangeable lens 4 is formed on the front plate portion 2-2 (2'-2), and the mount 2-4 (2°-4) Mount knob 2-5 that engages with the lens 4 mount claw and bayonet
(2'-5) is formed. In addition, the front plate part 2-2
(2'-2) has a recess 1-2 on the left side edge of the camera body 1.
A lock release button support piece 2-6 (2°-6) for attaching and detaching the interchangeable lens that is fitted to the holder 29 is protruded, and the finder unit 2 and A lock release button 2-7 (2'-7) is attached which is pressed to release the connection between the lens 2' and the interchangeable lens 4.

Rear part 2-1 (2'-1) and top plate part 2-3 (2
As shown in FIG. 16, in the space surrounded by )
, a condenser lens 2-10 (2°-101), and an eyepiece lens 2-11 (2°-11) are accommodated.

At a position below the focusing plate 2-9 (2°-9), there is a main mirror 2-12 for making the light beam incident on the focusing plate.
(2'-12') is arranged, and the mirror 2-12 (
2'-12°) is mirror support plate Z-26 (2°-26)
installed on. The mirror support plate is rotatably supported by the side frame of the finder unit 2 (2°) on a shaft 2-13 (2'-13) fixed to itself, and the mirror support plate is supported by a side frame (not shown). It is adapted to be moved by a mirror positioning mechanism.

In addition, the mirror 2 provided in the finder unit 2
Reference numeral 12 denotes a so-called movable mirror which is retracted from the photographing optical axis during photographing exposure, and is configured as a half mirror.

On the other hand, the mirrors 2'-12' provided in the finder unit 2' are composed of semi-transparent mirrors called so-called pellicle mirrors, and are so-called fixed mirrors that do not retreat from the photographic optical axis even during photographic exposure. .

In addition, as shown in FIG. 16, a photometric lens 2-- which constitutes a photometric device - is located inside the finder unit 2 (2°).
14 (2°-14) and photometric element 2-15 (2°-15
) is arranged close to the exit side surface of the pentaprism 2-8 (2'-81, and the pentaprism 2-8
The light flux emitted from (2'-8) is the photometric lens 2-1
4 (2'-14) through photometric element 2-15 (2°
-15).

The eyepiece 2-16 (2'-16) that holds the eyepiece lens 2-11 (2°-11) is the top plate part 2.
-3 (2°-3), and when the finder unit 2 (2°) is attached to the camera body 1, it is fitted into the recess 1-13 (Fig. 9) of the camera body frame. It has become.

Further, as shown in FIGS. 3 and 14, the front plate portion 2-2 (2'-2) of the finder unit 2 (2') has a surface 2 facing the surface 1-20 of the camera body 1. -1
7 (2°-17) and a surface 2-18 (2°-18) arranged opposite to the surface 1-21 of the camera body 1, and the surface 2-17 (2'-17) is A camera body connection contact group 2-19 (2'-19) is formed which is pressed into contact with the finder unit connection contact group 1-22 of the main body 1.

The two surfaces 2-17 (2'-17) and 2-18
In the optical path space between (2'-18), the main mirror 2
-12 (2'-12°) for keeping the mirror tilted forward at 45° with respect to the horizontal plane in the lowered position of the mirror 2-
20 (2'-20) protrudes from the side wall of surface 2-17 (2'-17), and main mirror 2-12 (2°
-12") is supported by the pin 2-20 (2°-20). The center of the main mirror support plate 2-26 is provided with the main mirror support plate 2-26 to direct the light flux that has passed through the photographing optical system to the sub-mirror 1-20. 1
A window 2-21 is provided to allow the light to enter 5.

The two surfaces 2-17 (2'-17) and 2-18
(2°-18) A pair of mounting pins 2-22 (2°-22) to be inserted into the mounting bin insertion holes 1-28 of the camera body 1 are protrudingly provided at positions below each of the mounting pins 2-22 (2°-18). In addition, the two surfaces 2-17 (2°-17) and 2-1
Lower edge 2-23 (2'-18) of the optical path space between 2'-18
'-23) is formed into an arcuate surface corresponding to the outer peripheral surface of the interchangeable lens 4.

Inside the finder unit 2 (2'), a data transmission line and a signal transmission line connected to the camera body connection contact group 2-19 (2'-19) are provided, and the transmission line is connected to the finder unit 2 (2'). 2').

Structure of Interchangeable Lens 4 The interchangeable lens 4 is equipped with a piellonet coupling type mount 4-3 having a mount claw 4-2 that engages with the mount claw of the finder unit 2 at the rear end, and as shown in FIG. As shown, the aforementioned camera body connection contact group 4-1 that contacts the lens connection contact group 4-1 of the camera body 1 is provided on the rear end surface.

The interchangeable lens 4 of this embodiment is of a type that incorporates a lens drive motor and an electric aperture device, and has almost the same structure as the interchangeable lenses already manufactured and sold by the present applicant. Therefore, a description of the functional structure of the interchangeable lens 4 will be omitted. (The electrical configuration will be explained later with reference to FIG. 7.) Structure of the finder unit 3 The finder unit 3 constitutes a part of the front plate of the camera body 1, as shown in FIG. a front plate portion 3-2; a rear portion 3-1 fitted into the space of the camera body 1;
The camera body 1 includes a top plate portion 3 - 3 that constitutes a top plate portion of the camera body 1 . At the center of the front plate portion 3-2, a lens barrel 3-4, which houses the entire photographic optical system and a part of the finder optical system, protrudes so as to be movable back and forth parallel to the optical axis. A finder window 3-5 for guiding a light beam to a finder optical system is provided on the distal end surface of lens 3-4. Further, a photometric window 3-6 is provided in the front plate portion 3-2, and the light beam passing through the photometric window 3-6 is incident on the photometric device.

A lens drive device for changing the magnification and focusing of the photographing optical system is provided within the lens barrel 3-4, and a control circuit for the drive device is also provided.

FIG. 18 is a schematic diagram showing the structure of the optical system with the finder unit 3 attached to the camera body 1. In the same figure, 3-9 is a photographing optical system provided in the lens barrel 3-4, and 3-1O is a photometry window 3 in the front plate portion 3-2.
3-11 is a photometric element into which the light beam passing through the photometric lens 3-10 enters; 3-12 is a finder optical system objective lens placed in the finder window 3-5; -13 is a finder optical system condenser lens provided in the finder unit 3, 3-
14 is an eyepiece lens, 3-15 is an eyepiece on the rear surface of the finder unit 3, and 1-15 is a photographic optical system 3.
- A sub-mirror provided within the camera body 1 to allow the light flux that has passed through the lens to enter the focus detection device 1-14;
It is.

FIG. 17 is a front view showing the back side of the finder unit 3. As shown in the figure, the back surface of the front plate portion 3-2 of the finder unit 3 includes a surface 3-16 that faces the front end surface 1-20 of the side wall portion of the camera body 1, and a front end surface 3-16 of the side wall portion of the camera body 1. A surface 3-17 opposite to the surface 1-21 is formed, and the surface 3-16 has a camera body connection contact group 3 that is pressed into contact with the finder unit connection contact group 1-22 of the camera body 1. -18 is formed. This camera body connection contact group 3-18 is provided for data transmission between the control device in the finder unit 3 (described later) and the control device in the camera body 1.
The contact group 3-18 is connected to a transmission line within the finder unit 3.

Reference numeral 3-19 is an arcuate vertical surface formed to face the surface 1-25 of the camera body 1, and the surface 3-19 is in pressure contact with the lens connection contact group 1-26 of the camera body 1. A group of cleavage contacts 3-20 is formed. The contact group 3-
Reference numeral 20 is provided for transmitting signals related to the lens barrel 3-4, and is connected to a signal transmission line within the finder unit 3.

Below the two surfaces 3-16 and 3-17 is a mounting bin 3 inserted into the mounting bin insertion hole 1-28 of the camera body 1.
-21 is provided protrudingly.

The eyepiece 3-15 of the finder optical system is fitted into the recess 1-13 of the camera body 1 when the finder unit 3 is attached to the camera body 1.

The interchangeable lens 4 and the finder unit 2 are connected by mounting them both in the same manner as in a normal camera. When connecting the finder unit 2 with the interchangeable lens 4 attached to the camera body 1, the finder unit 2
Insert the mounting bin 2-22 into the mounting bin insertion hole 1 of the camera body 1.
-28, and position the surfaces 2-17 and 2-18 to face the surfaces 1-20 and 1-21 of the camera body 1, respectively. As a result, the eyepiece 2-16 of the finder unit 2 is fitted into the recess 1-13 on the rear side of the camera body 1, and at the same time, the contact groups 1-22 and 2-19 for connection are pressed against each other.

Further, since the rear end surface of the interchangeable lens 4 carried by the finder unit 2 is positioned opposite to the surface 1-25 of the camera body 1, the lens connection contact group 1-26 of the camera body 1 is connected to the interchangeable lens 4. It is pressed into contact with the camera body connection contact group 4-1 on the rear end surface of the camera body.

When the finder unit 2 is attached to the camera body 1, the main mirror 2-12 is tilted forward to a position on the photographing optical axis as shown in FIG. 19 by a mirror positioning mechanism (not shown) in the finder unit 2. On the other hand, another mirror positioning mechanism within the camera body 1 positions the sub-mirror 1-15 in a backwardly tilted position immediately behind the main mirror 2-12, as shown in FIG.

When the camera user presses down the shutter release button 1-11 on the camera body 1 to the first step when taking a picture,
Photometry and distance measurement are performed, and the light flux that passes through the photographic lens 4-4 enters the main mirror 2-12, and the light beam passes through the photographic lens 4-4.
The light beam reflected on the surface of lens 2 enters a focusing plate 2-9 and a pentaprism 2-8, and then focuses an object image on an eyepiece of a finder optical system. On the other hand, main mirror support plate 2
The light flux passing through the window 2-21 of -26 is reflected by the sub-mirror 1-15 in the camera body 1 and enters the focus detection device 1-14, where the photographing optical system corresponds to the position of the subject. The focus of the image is detected. In this case, the imaging position of the light beam incident on the focus detection device 1-14 is a position A, which is a distance δ1 in front of the film F.

Therefore, the control device of the car camera performs a focusing calculation taking into account the deviation of δl, and instructs the lens drive control means in the interchangeable lens 4 to drive the lens based on the result of the calculation.

When distance measurement and focusing drive of the photographic lens are completed, the main mirror 2-12 moves to the focus plate 2-9 as shown in FIG.
At the same time, the sub-mirror 1-15 is also retracted from the photographing optical axis so as to cover the light beam incident surface of the focus detection device 1-14, and then the shutter operation is performed and the photograph is taken. The light flux passing through the lens 4-4 is incident on the film F, and a subject image is formed on the film F.

Immediately after the photographic exposure is completed, the main mirror 2-12 and the sub-mirror 1-15 automatically return to the positions shown in FIG. 19 and stand by for the next photograph.

The external shape of the finder unit 2° is exactly the same as that of the finder unit 2, but the finder unit 2′ has a built-in semi-transparent main mirror 2°-12°, and the main mirror 2°-12° is used even during shooting exposure. It is held in position on the optical axis.

Figure 21 shows the main mirror 2 of a second type SLR camera during non-photographing exposure (when no photographic exposure is being performed).
−12° and the state of submirror 1-15 are shown. During distance measurement before photographic exposure, a part of the light beam passing through the photographing lens 4-4 is reflected by the main mirror 2°-12' and enters the focus plate 2-9 of the finder optical system, while the main mirror 2°
The light beam that has passed through -12° is reflected by the sub-mirror 1-15 and enters the focus detection device 1-14. At this time, since the light flux that enters the focus detection device 1-14 is a light flux that forms an image on the film on the photographing optical axis, the control device in the camera performs a focusing f4 calculation that does not take into account deviation, and the calculation result is It is necessary to give an instruction to the lens drive control means in the interchangeable lens 4 to drive the lens based on this.

When distance measurement and focusing drive of the photographing lens are completed, in response to the second press of the shutter release button, the sub-mirror 1-15 moves to the focus detection device 1-1 as shown in FIG.
4, the shutter is operated, and the light beam passing through the photographing lens 4-4 forms an image on the film F.

this'! In the J%2 type SLR camera, the main mirror 2'-12' does not retreat from the photographing optical axis even during photographing exposure. Therefore, the focus of the light beam incident on the film surface is on the film surface. In this way, the focus control device (focus adjustment means) in the camera adjusts the focus differently from that of the first type R-type camera (i.e., Focus adjustment considering optical path length difference δ2)
need to be done.

When the finder unit 3 is attached to the camera body 1, R
An F-type camera is configured. In this case, the camera body connection contact group 3-18 of the finder unit 3 contacts the finder unit connection contact group 1-22 of the camera body 1, and the other camera body connection contact group 3-20 of the finder unit 3 contacts the finder unit connection contact group 3-22 of the camera body 1. contacts the interchangeable lens connection contact group 1-26 of the camera body 1 to complete the electrical connection as shown in FIG. Also, eyepiece 3 of finder unit 3
-15 is the recess 1-13 (9th part) on the rear side of the camera body 1.
(see figure), and the mounting bin 3-21 of the finder unit 3 is inserted into the mounting bin insertion hole 1-28 of the camera body 1 to mechanically connect the unit 3 and the camera body 1.

When the finder unit 3 is attached to the camera body 1,
The sub mirror 1- is moved by the operation of a mirror support mechanism (not shown).
15 is positioned on the photographing optical axis as shown in FIG.

When the camera user presses the shutter release button to the first step when taking a picture, photometry and distance measurement are performed, and the light flux passing through the photographic lens 3-9 is reflected by the sub-mirror 1-15 and sent to the focus detection device 1-14. incident on . The focus position of this light beam is on the film, and since the sub-mirror 1-15 falls down on the focus detection device 1-14 during photographic exposure as shown in FIG. 24, the focus of the light beam passing through the photographic lens 3-9 is The position can be placed on the film surface. However, if the camera's focus control device (focus adjustment means) is configured to correspond to the first type of SLR camera, δ1
This causes a misalignment, and the focal position cannot be aligned with the film surface during exposure.

In other words, even in the case of an RF type camera consisting of a finder unit 3 and a camera body 1, if the focus adjustment is performed in the same way as the first type SLR type camera, the focus cannot be adjusted on the film plane. Focus adjustment that is different from that of an SLR camera (that is, takes into consideration the optical path length difference δ) is required.

As described below, the photographing apparatus of the present invention includes a control means configured to perform focus adjustment in consideration of the optical path length difference for each finder unit. Since this control means is mainly composed of an electronic control device, the electrical configuration, function, and operation of each of the first type, second type, and third type cameras will be explained below.

If camera body 1 and finder unit 2 are shown in Figure 7,
FIG. 8 shows the electrical configuration of a first type and a second type breast R type camera configured by combining an interchangeable lens 4, a finder unit 2 or 2', and a camera body 1.
It shows the electrical configuration of a third type RF camera configured by combining a finder unit 3 and a camera body 1.

In addition, components indicated by the same reference numerals in FIG. 7 and FIG. They are mutually equivalent signals.

In FIGS. 7 and 8, PH1 is a computer that constitutes a control device within the camera body 1. For example, PH1 has a CPU (central processing unit) and R
1 chip with OM, RAM and A/D conversion functions
It is a microcomputer. Computer PR5 is R
A series of camera operations such as automatic exposure control function, automatic focus detection function, and film winding are performed according to the camera sequence program stored in the OM. For this purpose, PH1 uses synchronous communication signals SO, SI, SCt, K
.

SFB, Tsuyoshi Transition I No. 8 CLCM, C3DR, CDD
R, SF8, and SFC are used to communicate with peripheral circuits in the camera body and control circuits in the finder unit 2 and interchangeable lens 4 to control circuits and devices in the camera body and circuits and devices in the finder unit and interchangeable lens. control the behavior of

LCM is a lens communication buffer circuit that supplies power to the lens power supply when the camera is in operation, and
When the selection signal CLCM from the computer PR5 is at a high potential level (hereinafter abbreviated as "H"), it serves as a communication buffer between the camera and the lens.

That is, computer PR5 sets CLCM to H" and S
When predetermined data is sent from SO in synchronization with CL,
LCM is connected to 5CLK and SO via the camera-lens interface.
For each buffer signal LC, DCL is output to the interchangeable lens 4. At the same time, the signal DLC from the interchangeable lens 4
outputs the buffered signal as SI and sends it to the computer PR.
5 inputs the above SI as data from the interchangeable lens 4 in synchronization with 5CLK.

SDR is a drive circuit for the focus detection device SNS (indicated as 1-14 in Fig. 9), which is composed of a CCD line sensor, etc., and is selected when the signal (:SDR is H''), SO, SI , SCL from PH1.

The signal CK is the CCD driving clock φ1. The signal INTEND is a clock for forming φ2, and the signal INTEND is a signal that notifies PH1 that the accumulation operation has ended. The output signal OS of the focus detection device SNS is clock φ1. It is a time-series image signal synchronized with φ2, and after being amplified by the amplifier circuit in the SDR, it is output as AO5 to the computer PR5. Computer PR5 manually inputs AO5 from the analog input terminal, synchronizes with CK, and converts A/D using the internal A/D conversion function.
After D conversion, the data is sequentially stored at a predetermined address in RAM.

In addition, 5AGC, which is the output signal of the focus detection device SNS, is the output signal of the AGC (automatic gain control = Auto) in the device SNS.
This is the output of the sensor for Ga1n Control), and is manually input to the drive circuit SDR and used for image signal accumulation control in the device SNS.

SPC is a photometric element for exposure control that receives light from a subject via a photographic lens, and its output SFC is input to an input terminal of computer PR5 and used for automatic exposure control (AE) according to a predetermined program.

The LEDs are light emitting diodes provided in the finder units 2, 2°, and 3, and constitute a display device that displays in-focus or out-of-focus information. During a focusing operation, the focus information determined by the computer PR5 is input to the computer FPR5 in the finder units 2, 2' and 3, and the FPR5 drives the LED to display in-focus or out-of-focus. .

Switches SWI and SW2 are switches that are linked to the release button 1-11 of the camera body 1 shown in FIG. Turn on SW2 by lowering it. As will be described later, the computer PR5 performs photometry and automatic focus adjustment when SW1 is turned on, and performs exposure control and film winding using SW2 as a trigger. still,
SW2 is connected to the "interrupt input terminal" of the microcomputer PR5, and even if a program is being executed when SWI is on, an interrupt is generated when S1'12 is on, and the program can immediately proceed to a predetermined interrupt program.

MTRI is a motor for film feeding, mirror charging, and shutter spring charging, and its forward and reverse rotation is controlled by a motor drive circuit MDR1. P
Signals MIF and MI input from H1 to M[lR1
R is a signal for motor control.

MCI and MG2 are magnets for starting the running of the front and rear shutter curtains, respectively. Signals SMGI and 5MG2 energize the amplification transistors TRI and TR2, respectively, and shutter control is performed by PH1.

The signal DCL that is input to the computer LPR in the interchangeable lens 4 and the computer LPR5 in the finder unit 3 in synchronization with the LC is the data of the command from the camera body 1 to the interchangeable lens 4 and the finder unit 3. The lens driving operation is determined in advance.

The computer LPR5 in the interchangeable lens and the computer FPR5 in the finder unit 3 analyze the command according to a predetermined procedure and perform operations such as focus adjustment and aperture control.
Various parameters of the lens (open F number, focal length, coefficient of defocus amount versus extension amount, etc.) are output based on the output DLC.

In the embodiment, an example of a zoom lens is shown, and when a focus adjustment command is sent from the camera body 1, the focus adjustment motor LM is activated according to the driving amount and direction sent at the same time.
TR is driven by signals LMF and LMR to move the optical system in the optical axis direction and perform focus adjustment. The amount of movement of the optical system is monitored by the pulse signal 5ENCF of the encoder circuit ENCF and counted by a counter in the LPR5, and when the predetermined movement is completed, the LPR5 itself outputs the signals LMF, L
Set MR to L” to brake the motor LVTR.

Therefore, once a focus adjustment command is sent from the camera to the LPR5, the computer PR5 in the camera body does not need to be involved in lens driving at all until the lens driving is completed.

Further, when an aperture control command is sent to the LPR 5 from the camera body side, a stepping motor DMTR, which is known for driving the aperture, is driven in accordance with the aperture stage sent at the same time. Note that since the stepping motor can be oven controlled, an encoder is not required to monitor the operation.

ENCZ is an encoder circuit attached to the zoom optical system, and a computer LPR5 in the interchangeable lens manually inputs a signal 5ENCZ from the encoder circuit ENCZ to detect the zoom position. Lens parameters at each zoom position are stored in the computer LPR5 in the interchangeable lens and the computer LPR5 in the finder unit 3, and when there is a request from the computer PR5 in the camera body, LPR5 displays the current zoom position. The parameters corresponding to the parameters are sent to the computer PR5 in the camera body 1.

The SWF provided on the camera body 1 is the above-mentioned attachment detection switch, and this switch SWF detects the position of the finder unit 2 or 2° and 3 when the finder unit 2 or 2° and finder unit 3 are attached to the camera body 1. Surfaces 2-18 and 2'-18 and 3
-17 closes the operating bin 1-23 by pushing it.

When the computer PH1 is manually informed that the switch SWF is closed, the computer PR5 activates the computer Fi'R5 in the finder unit 2 or 2'' and 3.
It is determined which type of finder unit is attached by reading information stored in advance in the FILM in the camera. Then, the type of subsequent control operation and selection of control information are determined depending on the type of the finder unit.

For example, finder unit 2 with an interchangeable lens attached.
Alternatively, if it is detected that 2' is attached to the camera body, the photometry method and mirror drive method are determined to be compatible with the first type or second type SLR camera.

Electrical operation of the first to third types of cameras Next, the electrical control operations in each of the first to third types of cameras will be explained with reference to FIGS. 1 to 8.

Camera body 1, finder unit 2 or 2°,
Alternatively, if a power source (not shown) is turned on before attaching the finder unit 3, power supply to the computer PR5 is started, and the PH1 becomes operational. Therefore, when the finder unit 2 or 2° and the interchangeable lens 4, or the finder unit 3 and the camera body 1 are attached, the attachment detection switch SWF is turned on, and in response, the in-camera computer PR5 operates according to the flowchart shown in Fig. 3. Perform the indicated control action. This makes it possible to take a photograph, and the PH1 waits for the start of the control operation shown in the flowchart of FIG.

When the in-camera computer PR5 performs the control operations shown in the flowchart of FIG. 3, the type of finder unit and the type of interchangeable lens attached to the camera body 1 are determined, and information regarding the finder unit and the interchangeable lens is determined. is stored in the in-camera computer PR5.

Subsequently, the in-camera computer PR5 starts the control operation shown in the flowchart of FIG. That is, when the computer PR5 is powered on,
In step (002), it is determined whether the switch SWI (see FIG. 7) which responds to the first press of the shirt release button 1-11 (FIG. 9) is ON or not, and whether the switch SW1 is OFF or not is determined. Sometimes, the process moves to step (003) to clear all control flags and variables set in the RAM in the computer PR5, and then returns to step (002). If the switch SWI is not turned on, step (002) is executed. and step (003)
Repeat.

On the other hand, in step (002), switch SWI is turned off.
If N, the process advances to step (005) and executes a "photometering subroutine" for "exposure control." That is, in step (005) the computer PR5
After manually inputting the output 5spc of the photometric element SPC to the analog input terminal and performing A/D conversion, the optimum shutter control value and R-accurate aperture control value are calculated based on the converted digital photometry value. The calculation result is stored at a predetermined address in RAM. Then, at the time of shutter release, the shutter and aperture are controlled based on this calculation result.

After the photometry subroutine is executed in step (005), the computer PR5 proceeds to step (QQ6) and
Image signal input subroutine" is executed. The flow of this subroutine is shown in FIG. 5, and the computer PR5 acquires an image signal from the focus detection device SNS (1-14) by executing this subroutine.

The "image signal input subroutine" will be explained below.

When the "image signal human power" subroutine is called, the computer PR5 goes through step (101) and then steps (10).
In 2), the focus detection device SNS is caused to start accumulating optical images. Specifically, the microcomputer PR5 sends an "accumulation start command" to the sensor drive circuit SDR through communication.
Upon receiving this, the SDR sets the clear signal CLR of the photoelectric conversion element section of the focus detection device SNS to "L" and starts accumulating charges.

In step (103), the timer value of the self-running timer is stored in the conversion TI to store the current time.

In the next step (104), the state of the input INTEND terminal of the computer PR5 is detected, and it is determined whether or not storage has been completed. The sensor drive circuit SDR sets the signal INTEND to °L°° at the same time as the accumulation starts, and the focus detection device SNS
monitors the AGC signal 5AGC from , and when 5AGC reaches a predetermined level, sets the signal INTEND to H'';
At the same time, the charge transfer signal SH is set to "H" for a predetermined period of time to transfer the charges in the photoelectric conversion element section to the CCD section.

If the INTEND terminal is "H" in step (104), it means that the accumulation has been completed, and therefore, in step (104)
The process moves to step 8), but if the INTEND terminal is "L", it means that the unused storage has not been completed, so the process moves to step (105).

In step (105), the timer value T of the self-running timer is
A variable TE obtained by subtracting the time TI stored in step (103) from IMER is stored in the RAM.

Therefore, a variable TE representing the time from the start of accumulation to this point, the so-called accumulation time, is stored in the RAM. In the next step (106), the above variable TE and constant MA
XINT is compared, and if TE is less than MAXINT, the process returns to step (104) and waits for the completion of accumulation again. On the other hand, if TE is greater than or equal to MAXINT, step (109
) and forcefully terminate the accumulation. The forced accumulation is executed by sending an "accumulation termination command" from the computer PR5 to the sensor drive circuit SDR.

When the sensor drive circuit SDR receives the "accumulation end command" from the computer PR5, it sets the charge transfer signal SH to "H" for a predetermined period of time to transfer the charge in the photoelectric conversion section to the CCD section. In this way, step (107) Through the flow up to this point, charge accumulation in the focus detection device is completed.

In step (108), the image signal O of the focus detection device SNS is
A/ of the signal AO5 which is amplified by the sensor drive circuit SDR.
D conversion and storage of the digital signal in RAM i are performed as follows. That is, the sensor drive circuit SDR generates CCD driving clocks φ1 and φ2 synchronized with the clock CK from the computer PR5, and the clocks φl and φ2 are sent to the control circuit 5SCNT inside the focus detection device SNS.
, the focus detection device SNS receives a clock φ1. φ
2 drives the CCD section, and the charges within the CCD are outputted in time series from the output oS as an image signal.

This signal is amplified by an amplifier inside the sensor drive circuit SDR and then input as AO5 to the analog input terminal of the computer PR5. The computer PR5 synchronizes with the clock CK that it outputs and controls the A/
Perform D conversion and sequentially R convert the digital image signal after A/D conversion.
It is stored at a predetermined address in AM.

After inputting the image signal, step (109)
) returns the "image signal input" sub-chin.

Here, we return to the explanation of the main routine shown in FIG. 4 again.

After the above-described "image signal manual subroutine" is executed in step (006), focus detection calculation is executed in step (007). The focus detection calculation in this step is a method of repeatedly calculating the defocus DEF of the photographing lens based on the image signal taken in by STENBU (006), and the specific calculation method is described by the applicant. Since this method has already been disclosed in Japanese Patent Application No. 160824/1982, a detailed explanation of this method will be omitted.

After executing the focus detection calculation in step (007), the computer PR3 proceeds to the next step (008).

The subroutine included in step (008) determines whether the finder unit attached to the camera body 1 requires correction of the optical path length, and if necessary, adjusts the defocus calculated in step (007). Amount DEF
This is an "optical path length correction calculation" subroutine that adds correction to the optical path length correction calculation subroutine.

This "optical path length correction calculation" subroutine will be explained below with reference to FIG.

Note that this optical path length correction calculation has already been performed in Figs. 19 to 2.
As explained in FIG. 4, this calculation is for correcting the fact that the focus of the photographing optical system changes depending on the type of finder unit attached to the camera body 1.

When the optical path length correction calculation subroutine is called in step (007), the computer PR5 calculates the finder unit (
It communicates with the computer FPR5 in 2, 2', 3) and reads the ROM data of the computer in the finder unit. Then, the process proceeds to the next step (303), and the flag SWA is set to 1 (if SWA-1, optical path length correction is required;
If WA-0, optical path length correction is not required). Incidentally, whether it is 5WA-1 or 5WA-0 is detected by the computer PR5, for example, based on the state of the movable bin 1-23 of the camera body 1 or the state of a switch in the mounting pin insertion hole 1-28.

If the flag SWA is "1" in step (303), the computer PR5 determines that the finder unit 2 is attached to the camera body 1, and the step (304)
), and if it is 5WA-G, it is determined that the finder unit 2° or the finder unit 3 is attached to the camera body 1, and the process advances to step (305).

In step (304), the defocus amount 111EF (focus detection device 1-1
4 output) and store the corrected value DL in RAM.
Store in.

On the other hand, if the finder unit attached to camera body 1 is either finder unit 2° or finder unit 3, step (3)
05), the defocus amount DEF is directly stored in RAMk:i without making any correction to the defocus amount DEF.
pay.

FIG. 2 shows a second embodiment of the optical path length correction calculation subroutine. In this embodiment, the program is configured so that the optical path length can be corrected according to the unique characteristics of each finder unit.

In FIG. 2, when the optical path length correction calculation is called in step (401), the computer PR5 in the camera body 1 communicates with the computer FPR5 in the finder unit in step (402), and stores it in the ROM in the finder unit. The optical path length correction data δ is read out based on the data.

Note that the ROM in the finder unit stores data regarding the optical path length change δ between the time of photographing and the time of focus detection.

Next, computer PR5 executes step (403). That is, with the imported optical path length correction data δ,
The defocus amount DEF, which is the output of the focus detection device, is corrected. When step (403) is completed, the process proceeds to step (4041), and this optical path length correction calculation subroutine is returned.

The optical path length correction calculation subroutine of the first embodiment shown in FIG.
The optical path length correction subroutine of the second embodiment shown in FIG. Since it is configured to perform optical path length correction calculations for each type of unit, it can be used, for example, for finder units with different main mirror thicknesses, materials, and angles.
In the finder unit 3, correction calculations for best focus correction caused by the difference between AF@ and the lens pupil can also be performed.

Therefore, steps such as data storage, communication, and calculation in the case of best focus can be omitted.

Here, we return to the explanation of the main routine shown in FIG. 4 again.

After completing the optical path length correction calculation, the computer PR5 proceeds to step (009) and executes a "lens drive subroutine" in step (oo9).

The lens drive subroutine is a program shown in FIG. 6, and when this subroutine is called, the computer PR5 in the camera body 1 executes step (202). In step (202), the computer PR5
communicates with the computer LPR5 in the interchangeable lens 4 or the computer FPR5 in the finder unit 3, and the ROM in the PR5 or the RO in the FPR5
Two data “S” and r PTH stored in M
, is taken into PR5. Here, the data "S" is a coefficient representing the "defocus amount specific to the photographic lens versus the amount of protrusion of the focusing lens." For example, if the photographic lens is a single lens that extends entirely, "S" = 1, In the case of a zoom lens, "S" changes depending on each zoom position.

Further, data r PTH represents the amount of protrusion of the focusing lens per output pulse of the encoder ENCF which is linked to the movement of the focusing lens in the optical axis direction.

In Stella 7' (203), the computer PR5 calculates the lens drive amount PF according to the following equation.

FP=DLXS/PHT Here, DL is the defocus amount obtained from the output of the focus detection device.

After calculating the lens drive amount FP in step (203),
The computer PR5 proceeds to step (204) and calculates the lens drive amount FP by the computer LPR in the interchangeable lens 4.
5 or computer L in finder unit 3
The command is transmitted to PR5 to instruct the computer LPR5 to drive the lens. When a signal indicating the completion of lens driving is transmitted from the LPR 5 in the interchangeable lens 4 or the LPR 5 in the finder unit 3, the above lens driving subroutine is terminated and step (009) of the main routine is terminated.

After the lens drive is completed, the computer PR5 returns to step (002) and continues in step (005) until the switch SWI is turned off or the switch SW2 is turned on.
) to (tllll19) are repeatedly executed.

Thereafter, when the release button is further pressed and the switch SW2 is turned on, the interruption function is used to immediately move to step (010) and start the release operation, regardless of which step it is in.

In step (011), it is determined whether the lens drive is being executed. If it is, the process moves to step (ot2), a lens drive stop command is sent, the lens drive is stopped, and the process proceeds to step (013). . Also, step (01
If the lens is not driven in step 1), immediately proceed to step (013).

In step (013), the main mirror in the finder unit 2 is enlarged, but if the fixed mirror finder unit 2' or the range finder unit 3 is attached to the camera body 1, the sub mirror 1-1
Perform only the evacuation in step 5. This is executed by controlling the motor control signal IATR2 shown in FIGS. 7 and 8. In the next step (014), the aperture control value already stored in the "side light" subroutine of the previous step (005) is transferred to the computer LPR in the interchangeable lens 4.
5 to cause the LPR 5 to perform aperture control.

Whether or not the mirror up and aperture control in steps (013) and (014) have been completed is detected in step (015). Incidentally, whether the mirror is raised or not is confirmed using a detection switch (not shown) attached to the mirror.

Further, in the aperture control, whether or not the aperture device has been driven to a predetermined aperture value is confirmed through communication with the LPR5.

If either one is not completed, the process waits at this step and continues to detect the status. When both control ends are confirmed, the process moves to step (016).

In step (016), in the "light metering" subroutine of light step (005), the shutter is controlled using the shutter control value already stored, and the film is exposed.

When the shutter control is completed, the next step (017
), a command is sent to the computer LPR5 in the interchangeable lens 4 or the computer PR3 in the finder unit 3 to open the aperture, and then,
The mirror is lowered in step (018). Similar to mirror up, mirror down uses motor control signals M2F and M.
This is executed by controlling motor MTR2 using 2R. In this mirror down step, step (01
Similarly to 3), if the fixed mirror finder 2 or range finder 3 is attached to the camera body 1, only the sub-mirror is returned.

In the next step (019), similarly to step (015), the process waits for the mirror down and the aperture opening to be completed. When both mirror down and aperture opening control are completed, the process moves to step (020).

In step (020), by appropriately controlling the motor control signals MIR and MIR shown in FIGS. 7 and 8,
One frame of film is wound.

[Effects of the Invention] As explained above, the photographing device of the present invention has an optical path difference that corrects the optical path difference between distance measurement and photographing exposure depending on the type of finder unit attached to the camera body 1. Since the correction means is provided, accurate focusing can always be performed no matter what type of finder unit is attached to the camera body 1.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the operation and function of a first embodiment of the optical path length difference correction means provided in the photographing device of the present invention, and FIG. 2 shows the operation and function of the second embodiment of the optical path length difference correction means. FIG. 3 is a flowchart showing the functions of a program executed by the microcomputer in the camera body when the finder unit is attached to the camera body in the photographing device of the present invention, and FIG. Flowchart representing the main routine executed by the microcomputer, No. 5
The figure is a flowchart of the image signal input subroutine executed in step (006) of FIG. 4, and FIG.
FIG. 7 is a flowchart of the lens drive subroutine executed in step (009) in the figure. FIG. 8 is a schematic diagram showing the electrical configuration of the second type of SLR type camera; FIG. The figure is a perspective view of the four components constituting the photographing device of the present invention seen from the front, and FIG. FIG. 11 is an enlarged view of the electrical connection between the camera body 1 and the first or second finder unit 2 or 2', and FIG. 12 is an enlarged view of the electrical connection between the camera body 1 and the interchangeable lens 4. 13 is a rear view of the finder unit 2, FIG. 14 is a rear view of the finder unit 2, FIG. 15 is a rear perspective view of the interchangeable lens 4, and FIG. 16 is a rear view of the camera body 1. A schematic diagram of the optical system of the first type and second type SLR type cameras configured by combining the finder unit 2 (or 2') and the interchangeable lens 4, FIG. 17 is a rear view of the finder unit 3, Fig. 18 is a schematic diagram of the optical system of a third type RF camera configured by attaching the finder unit 3 to the camera body 1, and Fig. 19 shows the first finder unit 2, camera body 1, and interchangeable lens. 20 is a schematic diagram of the optical system at the time of focus detection of the first type RLS type camera, which is configured by combining 4 and 4. Fig. 20 is a schematic diagram of the optical system during photographing exposure of the first type SLR type camera shown in Fig. Schematic diagram of
FIG. 21 is a schematic diagram of the optical system during focus detection of a second type SLR camera configured by combining a second finder unit 2, a camera body 1, and an interchangeable lens 4, and FIG. FIG. 23 is a schematic diagram of the optical system of the second type SLR type camera during photographing exposure, and FIG.
Schematic diagram of the optical system during focus detection of the F-type camera, Part 2
FIG. 4 is a schematic diagram of the optical system of the RF type camera during photographing exposure. 1... Camera body 2.2'... Finder unit 3... Finder unit 1-3... Focal plane shutter 1-14...
...Focus detection device 1-15...Sub mirror 1-19...Main mirror drive lever 1-22...
Contact group for connecting the finder unit 1-26...Contact group for connecting the interchangeable lens and finder unit 1-28...Mounting pin insertion hole 2-12...Sub mirror 2-19...Contact group for connecting the camera body 2-22...
Mounting bin 2-15...Side light element 3-18...Camera body connection contact group 3-20...Camera body connection contact group 3-21...Mounting bin Figure 5 Figure 5 Figure 10 Figure 1 Figure 2 Figure Stomach - Figure 13 Figure 22 -23 -22 Figure 5

Claims (1)

[Scope of Claims] 1. A camera body that includes a built-in focus detection device for detecting the focus of a photographic optical system, and a finder optical system, and is configured to be detachably and replaceably attached to the camera body. In a photographing device having a plurality of types of finder units, the optical path length difference between the focal position of the photographing optical system at the time of focus detection and the focal position of the photographing optical system at the time of photographing exposure is corrected for each finder unit. A photographing device characterized in that an optical path length difference correcting means is provided.