JPS58178331A - Photographic or cinematographic camera having photographic lens and active type range finder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a photographing lens and an active rangefinder, the active rangefinder having a light emitter and a light receiver, and the light emitter emits at least one convergent light beam. , the optical imaging member has an optical imaging member having an optical axis oriented substantially parallel to the optical axis of the taking lens, the optical imaging member forming an illumination spot on the aiming object, and the optical imaging member has the optical imaging member in the imaging plane. projecting a substantially sharp image of the irradiation spot, and using the position of the imaging member in the imaging plane of the facial image relative to the optical axis as a measure of the object distance;
and relates to a photographic or cine camera of the type in which the light receiver has a detector movable along the imaging plane for detecting an image in the imaging plane.

Distance meter known for cameras (West German Patent Application No. 28)
53978), the optical axes of the rangefinder's light emitting device and the camera's photographing lens necessarily have a certain distance from each other, and this distance can be arbitrarily small for structural reasons. I can't. As a result, the light beam emitted from the light emitter parallel to the optical axis of the photographic lens hits a spot on the subject, and the spot is imaged off the optical axis on the imaging plane of the photographic lens. This image formation gap becomes wider as the shooting distance to the subject becomes smaller and the focal length of the shooting lens becomes longer. Optical axis distance a = 50
mm, focal length f = 55 mm and shooting distance e =
At 1 m, the deviation d from the subject image projected from the photographic lens to the optical axis of the photographic lens can be obtained from the formula: d = 2.7 force; For example, in a Super 3 type cine camera, this deviation is larger than half the image width of a Super 8 film (approximately 2.6 mm). In a camera without balax, such as a reflex camera or a rangefinder camera with vararax corrected, the optical axis of the photographing lens substantially coincides with the viewfinder optical axis, so the light rays leaving the emitter are directed toward the subject or subject spot. In this case, the spot is imaged off-center in the finder. As a result, instead of measuring the distance of the object at the center of the finder, the distance of the object shifted by the above amount from the center of the finder is measured. Moreover, in the above-mentioned example of the Super 8 system camera, the distance to an object located outside the finder is measured.

Therefore, in cameras where small objects at further distances are photographed from a number of different short distances, the above-mentioned deviations can lead to a distance measurement and an adjustment or automatic adjustment of the photographic lens. resulting in ambiguity regarding the selection of objects to be adjusted. As a result, an image is taken that is sharply focused not on the desired object but on an out-of-focus object adjacent to it, and as a result, an unsharp image is obtained even in close-range shooting.

By the way, in the camera of the type mentioned at the beginning, the light beam can rotate within a plane passing on the optical axis of the light emitter and the photographing lens, and the rotation of the light beam and the moving movement of the detector can be performed at any position of the detector. A photograph having an objective lens and an active rangefinder according to the present invention, characterized in that the irradiation spot formed by the light beam is located at a distance corresponding to the position of the detector on the optical axis of the photographic lens, or Cine cameras do not introduce such ambiguities, ie the object selected and imaged in the viewfinder is actually measured precisely with respect to its distance to the camera.

This is because the light beam starting from the emitter always appears at the center of the finder when the object is viewed, due to the combination of the beam rotation device of the present invention, the beam rotation within the emitter, and the movement of the detector within the receiver. This is because it is guaranteed that the optical axis of the photographing lens will be crossed at a position that coincides with the spot. This also applies to cameras in which the finder optical path extends through the taking lens (for example reflex cameras) as well as to rangefinder cameras in which the finder optical path extends parallel to the taking lens optical path (for example photographic or cine cameras).

In the first case, the optical axis of the viewfinder coincides with the optical axis of the taking lens, and in the second case, the parallax that occurs during close-up photography is sufficiently compensated for by the movement of the image restriction mark visible in the viewfinder. Corrected. In the latter case, the object measured by the rangefinder appears approximately at the center of the image, as if the variation between the finder and the photographic lens had been corrected. In this case, the light beam can be rotated by rotating the entire light emitter or by moving a projection lens placed in front of the light source transversely to the optical axis.

Advantageous embodiments and improvements of the camera according to claim 1 are possible by means of the measures specified in the embodiment section of the patent claim.

In this case, the embodiment according to claim 5 is particularly advantageous. The slit diaphragm ensures that no harmful images caused by reflections in the optics of the emitter and/or receiver reach the photodiode.

A further advantageous embodiment of the invention is also apparent from the patent claim 7. According to this means, the required length of the photodiode can be significantly shortened. Due to the specular surface, the significantly shortened photodiode can be used to control the detector even in the most undesirable case, i.e. when the emitter and receiver are adjusted to the maximum effective distance, and the aimed object is nevertheless at the shortest focusing distance. Detects the light pulses necessary for

Further advantageous embodiments of the invention also result from the patent claim 10. A suitable embodiment for this still photographic camera provides for a simplification of the diaphragm and a reduction in the photodiode size. Despite the large detector travel, a relatively small photosensitive area is sufficient for the photodiode. Again, the insensitivity to harmful images is virtually complete.

Advantageous embodiments of the invention are also apparent from patent claim 11. When the rangefinder is placed at its maximum effective distance (infinity adjustment position), the photodiode flashes, indicating to the photographer that the target object is closer than the shortest shooting distance inherent to the photographing lens.

Advantageous embodiments of the invention also result from the patent claims 12 and 16. This embodiment is advantageous if, for structural reasons, it is not possible to arrange the optical axes of the emitter, the receiver and the taking lens in a common plane.

The invention will now be described in detail with reference to the illustrated embodiments.

The camera shown in FIG. 1, which may be either a still photographic camera or a cine camera, includes a photographic lens 11 for photographing and an active rangefinder 12 within a casing 10.
has. The rangefinder 12 consists of a light emitter 13 that emits a narrow, focused beam of light 14, preferably infrared radiation, and a light receiver 20.

The light ray 14 is shown in FIG.
It is symbolically shown by two marginal rays 142 and 143. The light beam 14 consists of a concatenation of individual light pulses emitted by a laser diode 15. laser diode 1
The light emitted from the projection lens 16 is sharply focused by the projection lens 16 and is emitted as a sharply restricted light beam through the light emitting opening 17 having a circular cross section. This light beam strikes the object 18 whose distance to the camera is to be measured and forms thereon an impingement range or illumination spot 19 with a circular cross section;
Regarding this, West German Patent Application Publication No. 285397
It is described in detail in the specification of No. 8.

The light receiver 20 has an optical imaging element 21, which is preferably constructed as a condenser lens, which projects a substantially sharp image of the illumination spot 19 onto an imaging surface 22. The optical imaging member 21 is arranged on an imaging surface 22 so that all the illumination spots 19 on the subject 18 at different distances in front of the camera can be sharply imaged on the imaging surface 22. is the angle δ with respect to the optical axis 23 of the imaging member 21. It is highly sloping. Angle δ. is the focal length of the optical imaging member 21 and the distance b from the optical imaging member to the optical axis 24 of the photographing lens 11
Depends on 2.

The imaging position of the irradiation spot 19 on the imaging plane 22, more precisely the distance of the facial image from the focal point F of the optical imaging member 21, is one measure of the distance from the camera to the subject 18. In order to detect the image on the imaging plane 22, the detector 25 is arranged movably along the imaging plane 22. For this purpose, as described in detail in DE 28 55 978 A1, the detector 25 can be driven by a drive, which is controlled via a control circuit 26, which forms the control signal for the drive from the output signal of the photodiode 27 (FIG. 3) associated with the photodetector 23.

In the embodiment of the camera shown in FIG.
The optical axes 28 of the projection lenses 16 are arranged in a common plane corresponding to the plane of the paper in FIG. in this case,
In this arrangement, the optical axes 28 and 23 of the light emitter 13 and the light receiver 2o are considered to be opposed to each other in the diametrical direction of the photographic lens 11. In this case, the optical axis 28 of the light emitter 13 has a distance bl from the optical axis 24 of the photographic lens 11.

The emitter 13 is configured in such a way that the light beam 14 can be rotated in a plane 29 . In this case, the rotation of the light beam can be effected by correspondingly rotating the entire emitter or, in the case of a fixed light source 15, by transversely moving the projection lens perpendicular to the optical axis 28. In order to rotate the optical axis 14, a beam rotation device 3o is provided, which device is connected to the drive of the detector 25 in such a way that the beam rotation is synchronized with the rotation movement of the detector 25. This synchronization is fixed and the exposure spot 1 formed by the light rays 1 and 4 at each position of the detector 25 along the imaging plane 22
9 is at a distance corresponding to the detector position on the optical axis 24 of the taking lens. By this means, the detector 2
5, as the distance to the optical axis 23 of the coupling member 21 or the focal point F in the imaging plane 22 increases, the angle α between the optical axis 14 and the photographing lens optical axis 14 increases, and vice versa. It will be done. In the distance meter 12, the detector 25
is always adjusted to the imaging of a flat limiting edge of the exposure spot 19 of circular cross-section, as shown in detail in DE 28 53 978 A1.
Light ray 140 and ambient light 142 intersect optical axis 24 at a distance corresponding to the detector position. The rotation of the ray 14 is the angle value α-D %
jan-”p.

In the above formula, pO represents the inherent shortest photographing distance of the photographing lens 11.

The photodiode 27 of the detector 25 is covered by a diaphragm 32 with a flat limiting edge 33, which is preferably designed as a slit diaphragm 34 (FIG. 4), in order to eliminate harmful images. In this case, the longitudinal axis of the slit blend 34 extends in the direction of movement of the detector 25 within a plane 29 through which the optical axes of the light emitter 13, the light receiver 20, and the photographic lens 11 pass.

As described in EP 2 853 978 A1, the photodiode 27 covered by this aperture 32 or 34 is fixed to a support driven by a servo motor. The servo motor is controlled by a control circuit 26. In the case of the invention, the control circuit 26 has a discriminator with two detection thresholds, as shown in FIG. Both detection thresholds are above the noise level and are slightly offset from each other.

Such a discriminator can consist of two comparators with different threshold values whose inputs are connected to the outputs of the photodiodes 27. When the pulse amplitude emitted by the photodiode 27 exceeds the upper detection threshold 36, the servo motor drives the detector 25 in the direction of the shortest distance, in which case the detector moves along the imaging plane 22 in the direction of arrow A. exercise. If the pulse amplitude emitted by the photodiode 27 does not reach the value of the lower detection threshold 35, a movement in the direction of adjustment of infinite distance takes place, in which case the detector moves along the imaging plane 22 in the direction of arrow B. move in the direction. Finally, when the pulse amplitude reaches a value lying between the two detection thresholds 35 and 360, equilibrium is achieved and the detector 25 is stopped.

Next, the mode of operation of the camera will be explained.

It is assumed that a sharp image of a subject 18 located at a distance p in front of the camera is to be formed. The subject 18 is aimed by a camera finder (not shown) so that the subject 18 is focused on the center of the finder image. If by chance the camera is focused at this distance p, the light ray 14 and the optical axis 2 of the photographic lens 11 will be aligned as shown in FIG.
The intersection point 31 of 4 is sharply imaged in the vertical position 3 within the imaging plane 22. The distance from position 1 to focal point F is calculated from the formula: where f is the focal length of optical imaging member 21. The angle β is obtained from the formula: From equations (2) and (6), the following equation is obtained. τ is a monotone function of the distance p only when the point of incidence of the light ray 140 on the subject 18 is on the optical axis of the photographic lens 11.

The instantaneous distance from the detector 25 to the focal point F is indicated by 〒. Under the precondition that the point of incidence of the light beam is on the photographic lens 24, the distance p is a function of τ [p-ψ(T)].

The rotation angle α of the light ray 14 is obtained from the equation 2 tan α-2 (5). Therefore, due to the combination of the displacement movement of the detector 25 and the rotation of the light beam 14, the equation: %Formula %In the position shown in FIG. It has been adjusted.

When the object distance is shorter than the distance p(α) corresponding to the instantaneous slope α shown in FIG. 1, that is, when the object 18 is between the camera and the intersection point 31 shown in FIG. The irradiation spot 19 is located on the left side of the optical axis 24 of the photographing lens in FIG. 1, and the image of the irradiation spot 19 is moved in the direction of arrow B within the imaging plane 22. Thereby, the imaging of the illumination spot 19 on the photodiode 27 moves beyond the limiting edge 33 and completely impinges on the photosensitive surface of the photodiode 27 . The amplitude of the light pulse thus sensed exceeds the detection threshold above the discriminator and the detector 25
2 in the direction of the arrow B, and as the detector 25 moves in the direction of the arrow B, the angle α is also enlarged due to the fixed combination of the moving movement of the detector 25 and the pivoting movement of the light beam 14. If now exactly the limiting edge of the imaging of the circular cross-section illumination spot 19 coincides with the limiting edge 33 of the diaphragm 32 or 34, the sensed pulse will still be attenuated and its amplitude will be equal to the detection thresholds 35 and 36 of both. It reaches the "death range" between. Equilibrium is thereby again achieved. If the distance from the camera to the subject is greater than the distance p(α) corresponding to the instantaneous slope α, the irradiation spot 1
9 is located on the right side of the photographing lens 24 in FIG. The entire image of the irradiation spot 19 hits the aperture 32 or 34, and the photodiode 27 receives no light t2. Therefore, the lower detection threshold of the discriminator is not achieved and the detector 25 is forced to move in the direction of the arrow until equilibrium is again achieved. In this case, the angle α will be small.

Finally, if the object is outside the maximum effective range of the rangefinder 12, the detector 25 is stopped only after the corresponding end position has been achieved, in which case the taking lens is adjusted to the superfocal distance.

In order to move the detector 25 in the desired direction even in the most undesirable case, the photodiode 27 transmits the necessary light pulses for its control, while the distance is pre-adjusted to the longest distance. Consideration should now be given to obtaining images even if the object 18 to be aimed at is at the shortest distance.

Therefore, the theoretical length of the photodiode 27 should match at least the maximum imaging movement amount, and the movement amount is determined by the shortest photographing distance p of the photographing lens 11 as shown in equation (4). It can be obtained by substituting . However, due to the mirror surface 37 shown in FIGS. 6 and 4, the photodiode 27
The length can be significantly shortened. This mirror surface 37 projects approximately perpendicularly from the diaphragm surface and is preferably integral with the slit diaphragm 34. In this case, the slit diaphragm 34 and the mirror surface 37 are formed from thin plates. Since the perceived light intensity is significantly greater at short distances, no special qualities are necessary for manufacturing the mirror surface.

In the case of still photography cameras, focusing is generally done on a non-moving subject, so the rangefinder
2 need not be configured for continuous tracking. In this case, instead of the diaphragm 32 or 340 with the mirror surface 37 of FIGS. 3 and 4, the slit 39 is approximately 5/ID 0 mm measured parallel to the direction of movement A-H and its length is A simple aperture 38 of a few tenths of a millimeter (Figure 5)
can be used. The photodiode 270 dimensions can then be correspondingly shortened. When using this aperture 38, the discriminator only has a single detection threshold whose level is slightly above the level of the noise. In this case, the detector drive device ensures that the detector 25 is positioned at the shortest imaging distance p before every measurement. should be controlled to take a position corresponding to From this position, the detector 25 is moved in the direction of the long adjustment distance, i.e. along the imaging plane 22 in the direction of arrow A, the photodiode 27 is excited and the corresponding output signal of the discriminator stops the detector 25. be forced to move up to

If the object distance exceeds the rangefinder's effective distance, i.e. the photodiode current does not reach the cut-off level,
The detector 25 is stopped when a position corresponding to the superfocal distance is achieved.

The super focal length is closest to the true distance of the subject.

The above-mentioned slot and slit dimensions of the diaphragm 39 are obtained from the imaging size of the irradiation spot at the upper limit of the effective distance of the range finder 12.

At large distances the illumination spot 19 has a square shape.

The aperture 38 of FIG. 5 has two significant advantages. On the - side, a relatively small photosensitive surface is sufficient despite the large imaging movement path, and on the other side there is complete insensitivity to harmful images.

When the distance of the subject 18 is smaller than the shortest photographing distance specific to the photographing lens, the photodiode 27 is connected to the detector 25.
During the 0 scan, the detector is not excited and is stopped only at the infinity adjustment position of the taking lens 11. In order to indicate that the selected shooting distance is too short, another photodiode 40 is provided, as shown in dashed lines in FIG. 10 controls an alarm display device 41 that can be seen from the outside. In this case, the photodiode 40 is arranged so that at least a portion of the light beam detected by the light receiver 20 from the subject 18 located at a distance shorter than the maximum allowable photographing distance impinges on another photodiode 40 . As soon as the alarm display device 41 reaches the rangefinder or photographic lens adjustment position, a clear display command for photographing is issued.

In the camera, the optical axes 23, 24, and 28 of the light receiver 20, the photographing lens 11, and the light emitter 13 are on a common plane 29.
Starting from being placed inside. however,
This is often not possible for constructional reasons, so that, for example, the emitter and receiver may be placed on either side of the taking lens 110, as schematically shown in FIG.
is placed above. In FIG. 6, the photographic lens 11
, a schematic plan view of the projection lens 16 of the emitter 13 and the optical imaging member 21 of the receiver 20 is shown. Photography lens 1
The optical axis 24 of 1 forms two relatively inclined optical axes 42 and 45 with the optical axes 23 and 28 of the receiver 20 and the emitter 13 (FIGS. 6 and 8). Taking lens optical axis 2 shown in Figure 7
In a perpendicular projection onto a plane in the plane of the paper of FIG. This side 42
There is an image plane 22 perpendicular to the image plane 22 , the intersection line of the image plane on the plane 42 is a straight line 44 , and the straight line 44 is at an angle δ with respect to the optical axis of the optical member 21 . It is highly sloping. When the irradiation spot 19 is on the subject 18 on the optical axis 24 of the photographic lens 11, that is, when the rangefinder is in equilibrium, the imaged spot 19 is imaged in the plane 42 and on the straight line 44. Ru.

However, outside the equilibrium state, the respective illumination spot 19 is no longer imaged in the plane 42 . As can be most easily understood from FIG. 7, outside the equilibrium state, the image of the illumination spot 19 passes through the point of penetration of the optical axis 24 of the taking lens 24 and the optical axis 28 of the projection lens 16 in the projection drawing, no matter where it is located. It is on the straight line CpR. If the imaging of the illumination spot 19 is between R and ob, the photodiode 27 cannot receive the pulse, since the rangefinder should move towards a larger distance. It is. On the other hand, if the exposure spot 19 is imaged between ob and Cp, the photodiode should be illuminated by the light beam. In the first case, the image of the irradiation spot 19 appears on the I side in the image plane 22, and in the second case on the ■ side (FIGS. 7 and 8). The detector 25 now has a photosensitive surface of the photodiode 27 extending in or parallel to the imaging plane 22 and a longitudinal axis of the slit diaphragm 34 covering the photosensitive surface of the photodiode 27 lying in or relative to the imaging surface 22 . It extends parallel and perpendicular to a plane 42 passing through the optical imaging member 21 of the receiver 20 and the optical axes 23 and 24 of the taking lens. In this case, slit aperture 3
The control edge 33 that limits 4 in the longitudinal direction is a straight line 44 of the surface 42.
It is above. Emitter 13, receiver 20 in the camera casing 10 and in the direction of the detector 25 along the imaging plane 22
With the exception of the different arrangement of the taking lens 11, the construction and operation of the camera shown in FIGS. 6 to 8 are identical to the first described camera embodiment.

The present invention is not limited to the above embodiments. Aperture 3
The detector 25 is always adjusted so that the limiting edge 33 of 2 or 34 approximately coincides with the flat limiting edge of the illumination spot 19. It is not an essential requirement that the rangefinder be constructed on the light receiving side, similar to the rangefinder described in DE-A-2853978. Detector 2 within the receiver 20
The adjustment to the imaging of the 5 illumination spots 19 can also be carried out using two differential photodetectors or a linear photodetector.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the optical path of the camera, photographic lens, and rangefinder, Fig. 2 is a schematic diagram showing the time course of the detection signal, and Fig. 3 is the light reception of the rangefinder shown in Fig. 1. 4 and 5 are perspective views of the detector in the light receiver of the rangefinder according to the second and third embodiments, respectively. FIG. 6 shows the arrangement of the photographing lens. FIG. 7 is a vertical projection of the objective lens arrangement shown in FIG. 6 projected onto a plane perpendicular to the photographing direction. 8 are perspective views showing the arrangement of detectors in the light receiver of the camera according to the second embodiment. 11...Photographing lens, 12...Distance meter, 13...
Light emitter, 14... Ray, 18... Subject, 19...
- Irradiation spot, 20... Light receiver, 21... Imaging member, 22... Imaging surface, 23... Optical axis of imaging member, 2
4... Optical axis of photographing lens, 25... Detector, 26...
... Discriminator (control device), 27... Photodiode, 28... Optical axis of light emitter, 29... Surface, 33...
Control edge, 34... Slit aperture, 37... Mirror surface, 3
8...Slit aperture, 40...Photodiode,
41...Alarm display device, 42.45...Mentang, 2 3536

Claims (1)

[Claims] 1. A photographing lens and an active rangefinder, the active rangefinder having a light emitter and a light receiver, and the light emitter emits at least one convergent light beam to target a target object. the optical imaging member has an optical imaging member having an optical axis oriented substantially parallel to the optical axis of the taking lens; for projecting a substantially sharp image, using the position of the imaging member in the imaging plane of the facial image relative to the optical axis as a measure of object distance, and for the receiver to detect the imaging in the imaging plane. In photographic or cine cameras of the type with a detector movable along the imaging plane, the plane (29) in which the light beam (14) passes on the optical axis (28, 24) of the emitter (13) and the photographic lens (11) ) (19
) is coupled at a distance corresponding to the detector position on the optical axis (24) of the photographic lens and an active rangefinder. 2. The light beam has a flat border on at least one side and the detector is adjustable to image the border substantially in the image plane of the receiver and on the optical axis (24) of the taking lens; Within a certain irradiation spot (19), the boundary line is the optical axis of the photographing lens (24).
) intersects the camera according to claim 1. Detector (2) from the optical axis (23) of the imaging member (21)
5) movement of the detector (25) such that as the distance increases, the angle (α) formed by the light beam (14) and the optical axis (24) of the taking lens increases and vice versa; 3. Camera according to claim 1, characterized in that the movement and the pivoting movement of the light beam (14) are fixedly coupled. 4. Photographic lens (11), light emitter (13) and light receiver (
20) whose optical axes (24, 28, 23) are in the plane (29) and the emitter (13) and the receiver (20) are advantageously arranged diametrically opposite the taking lens (11). The camera according to any one of claims 1 to 6. 5. The detector (25) has a photodiode (27), the photosensitive surface extending within or parallel to the imaging plane (22) of the photodiode is limited by a slit diaphragm (34); The detector (
The discriminator (25) extends in the direction of movement of the discriminator (25) and the rangefinder (12) has two detection thresholds that are slightly offset from each other.
6), and the input side of the discriminator is a photodiode)'(
Claim 4 connected to the output side of 27)
Camera mentioned in section. 6. Camera according to claim 5, in which the slit diaphragm (34) extends over the entire travel path of the detector (25). The Z slit diaphragm (34) extends only over a part of the travel path of the detector (25) and is located approximately from the slit surface at the end opposite to the optical axis (23) of the imaging member (21) in this travel. Camera according to claim 5, having a mirror surface (37) projecting at right angles. 8. The camera according to claim 7, wherein the slit diaphragm (34) and the mirror surface (37) are made of an integral thin plate. 9 Optical axis of optical member (21) of slit diaphragm (34)
The limiting edge (33) facing 23) at the maximum effective distance of the rangefinder (12) at which the illumination spot (19) formed by the light, l1f (14), is exactly still on the photodiode (27) The optical axis (23
), Claims 5 to 8 1)
If the camera described in item 1. 10. The detector (25) has a photodiode v (27), the photosensitive surface of which extends within or parallel to the imaging plane (22) and is controlled by a slit diaphragm (38). The horizontal axis of the slit diaphragm is the light emitter (1
3), the optical axis of the light receiver (20) and objective lens (11) (
28, 23, 24), the detector (25)
), the rangefinder (12) has a discriminator (26) with a unique detection threshold, the input side of the discriminator being connected to the output side of the photodiode (27); and a control device (26) for controlling the movement of the detector (25);
) always starts the distance measurement operation, the distance from the optical axis (23) of the imaging member (21) measured along the imaging plane (22) corresponds to the adjustment position for the shortest focusing distance specific to the taking lens. 5. A camera according to claim 4, wherein the camera is configured to be in a basic position. 11. A subject (18) that has another photodiode (40) that controls an alarm display device (41), and the photodiode-V is within a distance shorter than the allowable shortest photographing distance.
Claim 10, characterized in that the photodiode (40) is arranged in such a way that at least a portion of the light beam (14) detected by the photoreceiver (20) falls on the photodiode (40). Camera listed. 12. Optical axes (24, 28, 23) of the photographic lens (11) and the light emitter (13), and the photographic lens (11) and the light receiver (20)
) are respectively one of the two relatively inclined surfaces (45, 42)
and preferably a light emitter (13) and a light receiver (20).
) are arranged on both sides of the photographing lens (11). 16. The detector (25) has a photodiode (27), and a photosensitive surface extending parallel to the imaging plane (22) of the photodiode is limited by a slit diaphragm (34), and the slit diaphragm (42) whose longitudinal axis passes through the optical axis (24, 23) of the photographing lens (11) and the light receiver (20)
) in a plane (42) in which an edge (33) that extends perpendicularly to the slit diaphragm (34) and limits the slit diaphragm (34) in the longitudinal direction passes through the optical axis (24, 23) of the photographing lens (11) and the light receiver (2o). 13. A camera according to claim 12.