Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
LARGE FORMAT CAMERA
Document Type and Number:
WIPO Patent Application WO/2001/037041
Kind Code:
A1
Abstract:
The present invention relates to a large format camera, which comprises a first camera (1) with a longitudinal centre axis (C), said first camera (1) comprising a first bellow (3), a first lens (5) having a shutter function and a film (7) for exposure, said first lens (5) being arranged at one end of the first camera (1) and the film (7) being arranged at the other end of the first camera (1). The invention also relates to a method for photographing in large format. Significant for the large format camera according to the present invention is that a second camera (1') is arranged with its longitudinal axis (C') perpendicular to the longitudinal axis (C) of the first camera (1), said second camera (1') comprising a second lens (5') and means (9') for sharpness information, that the second lens (5') is provided at one end of the second camera (1'), that the means (9') for sharpness information is provided at the other end of the second camera (1'), that the large format camera also comprises a mirror (10) that in active position is located in front of the lenses (5, 5'), that said mirror (10) in its active position is located in the intersectional point of the longitudinal centre axis (C) and (C') and lies on the bisector of the right angle between the longitudinal centre axes (C) and (C'), that the large format camera comprises means to transfer the mirror (10) from said active position to an inactive position beside the lenses (5, 5').

Inventors:
BESKOW MARTIN (SE)
Application Number:
PCT/SE2000/002228
Publication Date:
May 25, 2001
Filing Date:
November 14, 2000
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
INSTAMAX AKTIEBOLAG (SE)
BESKOW MARTIN (SE)
International Classes:
G03B19/14; (IPC1-7): G03B19/14
Foreign References:
US0852476A1907-05-07
US3653314A1972-04-04
Attorney, Agent or Firm:
Eriksson, Kjell (Norrtelje Patentbyrå AB P.O. Box 38 Norrtälje, SE)
Download PDF:
Claims:
Claims
1. Large format camera, which comprises a first camera (1) with a longitudinal centre axis (C), said first camera (1) comprising a first bellow (3), a first lens (5) having a shutter function and a film (7) for exposure, said first lens (5) being arranged at one end of the first camera (1) and the film (7) being arranged at the other end of the first camera (1), c h a r a c t e r i z e d in that a second camera (1') is arranged with its longitudinal axis (C') perpendicular to the longitudinal axis (C) of the first camera (1), said second camera (1') comprising a second lens (5') and means (9') for sharpness information, that the second lens (5') is arranged at one end of the second camera (1'), that the means (9') for sharpness information is arranged at the other end of the second camera (1'), that the large format camera also comprises a mirror (10) that in active position is located in front of the lenses (5,5'), that said mirror (10) in its active position is located in the intersectional point of the longitudinal centre axes (C) and (C') and lies on the bisector of the right angle between the longitudinal centre axes (C) and (C'), that the large format camera comprises means to transfer the mirror (10) from said active position to an inactive position beside the lenses (5,5'), and that the large format camera comprises means to release the shutter function of the first lens (5) when the mirror (10) is in its inactive position.
2. Large format camera according to claim 1, c h a r a c t e r i z e d in that the means to transfer the mirror (10) from active to inactive position comprises a power source (20) and endless transmission means (11,14) driven by the power source (20), said transmission means running around pulley wheels (12,12,15,16), and that the mirror (10) is suspended in said endless transmission means (11,14).
3. Large format camera according to claim 2, c h a r a c t e r i z e d in that a counterweight (17) of the mirror (10) is suspended in said endless belts (11,14).
4. Large format camera according to any of the previous claims, c h a r a c t e r i z e d in that the means to transfer the mirror (10) from active to inactive position is designed in such a way that the mirror (10) on one hand is given an acceleration and on the other hand is given a retardation.
5. Large format camera according to any of the previous claims, c h a r a c t e r i z e d in that the means to release the shutter function of the first lens (5) comprises on one hand an activating means, influenced by the mirror (10), and on the other hand a cable release that extends between the activating means and the shutter function.
6. Method for photographing by means of a large format camera, c h a r a c t e r i z e d in that light rays (S) are deflected by means of a mirror (10) and refracted by means of a second lens (5'), said light rays (S) being emitted from an object (M) that is about to be photographed, that the distance between said second lens (5') and a means (9') for sharpness information is adjusted, that in connection therewith the distance between a first lens (5) and a film (7) for exposure is adjusted automatically to a corresponding degree, and that subsequently the deflection of the light rays (S) are interrupted, the light rays (S) from the object (M) passing the first lens (5), is refracted in said lens (5) and hits the film (7) for exposure of the film (7).
7. Method according to claim 6, c h a r a c t e r i z e d in that the deflection is interrupted by giving the mirror (10) a linear displacement in its main plane.
8. Method according to claim 6 or 7, c h a r a c t e r i z e d in that the light that passes through the first lens (5) is controlled by the shutter function of the first lens (5).
Description:
LARGE FORMAT CAMERA Technical Field of the Invention The present invention relates to a large format camera, which comprises a first camera having a lens and a film for exposure, said lens being arranged at one end of the camera and the film being arranged at the other end of the camera.

The invention also relates to a method for photographing in large format.

Prior Art Photographing in large format according to prior art is in principle restricted to photographing of objects where no continuous information about the sharpness is required.

Examples of such objects are products. So called large format film is available in different seizes, from 9x12 to 8x10 inches (about 18x24 cm). The working procedure in connection with large format photographing is that the photographer initially adjusts the sharpness and then load the camera with film sheets in the shape of a cartridge that protects the film from light. When it is time for exposure a shading cover is removed from the cartridge and it is possible to exposure the film.

A problem in connection with large format photographing according to prior art is that it is not normally possible to photograph human beings with a maintained sharpness. However, attempts are made but it is required that the person/persons in question is/are absolutely still during the time that the photographer is engaged with the film cartridge and the removal of the shading cover, i. e. after the adjustment of the sharpness has been made. Since the requirement of the sharpness is extremely high it is usually difficult to maintain the sharpness up to the exposure.

Objects and Features of the Invention A primary object of the present invention is to define a large format camera that gives the photographer continuous information about the sharpness in principle up to the moment of exposure.

A further object of the present invention is to define a large format camera that is extremely user friendly.

Still an object of the present invention is to define a large format camera that, according to a preferred embodiment, has a structurally simple design.

Brief Description of the Drawings Below a preferred embodiment of a large format camera according to the present invention will be described, reference being made to the accompanying drawings, where Fig 1 schematically shows the fundamental structural design of a large format camera according to the present invention, a mirror included in the camera being in active position; Fig 2 schematically shows the corresponding structural design as in Fig 1, however the mirror included in the camera is in inactive position; Fig 3 shows a top view of an embodiment of a large format camera according to the present invention; Fig 4 shows a top view of the displacement mechanism of the mirror included in the large format camera; Fig 5 shows a side view of the displacement mechanism of the mirror included in the large format camera, Fig 6 shows a side view of how a camera of a certain seize is attached to a bracket included in the large format camera; Fig 7 shows a corresponding side view as in Fig 6 of a camera of a different seize than the camera shown in Fig 6.

Detailed Description of a Preferred Embodiment of a Large Format Camera according to the Invention and a Method for Large Format Photographing As is evident from Fig 1 a large format camera according to the present invention comprises a first camera 1, that in a usual way comprises a first bellow 3, a first lens 5 and means for receiving a cartridge 7 that includes film sheets. The first lens 5 is arranged at one end of the first bellow 3 while the cartridge 7 is provided at the other end of the first bellow 3.

The large format camera according to Fig 1 also comprises a second camera 1'that comprises a second bellow 3', a second lens 5'and a focusing screen 9'that constitutes means for continuous sharpness information. The second lens 5'is provided at one end of the second bellow 3'while the focusing screen 9'is provided that the other end of the second bellow 3'. The first and second cameras 1 and 1' respectively are oriented with their longitudinal axes C and C'respectively perpendicular to each other.

As is evident from Fig 1 the large format camera according to the present invention comprises also a surface coated mirror 10, said mirror 10 being oriented in such a way relative to the cameras 1,1'that the reflecting surface of said mirror 10 forms an angle a with the longitudinal axis C of the camera 1 and a angle a'with the longitudinal axis C' of the camera 1', i. e. the reflecting surface of the mirror 10 is located in the intersectional point between the axes C and C'. Both said angles a, a'have a value of 45°, i. e. the reflecting surface of the mirror 10 is located on the bisector of the right angle between the longitudinal axes C and C'.

The first and second bellows 3 and 3'respectively have the same length L and L'respectively and the distances D and D'respectively have the same seize, said distances extending between the intersectional point of the axes C and C'and the respective refracting plane of the lenses 5 and 5'. This means that the distance D+L between the intersectional point of the axes C and C'and the cartridge 7 is of the same size as the distance D'+L'between the intersectional point of the axes C and C'and the focusing screen 9'. A prerequisite for this is of course that the lenses 5 and 5'have the same focal length.

In Fig 1 an object M is also disclosed, said object being photographed by means of the large format camera according to Fig 1. In connection therewith light rays S emit from the object M, said light rays S hitting the mirror 10 and being reflected in said mirror 10. The centre ray, being denoted SC, is then coinciding with the longitudinal axis C' of the second camera 1'. Subsequently the rays S hit the focusing screen 9'after having passed the lens 5'and being

refracted in said lens 5'. The sharpness is adjusted by adjusting the length L'of the second bellow 3', the large format camera according to the present invention being designed in such a way that the adjustment of the length of the second bellow 3'is automatically transferred to an adjustment of also the length of the first bellow. For reasons of clarity this is shown schematically only in Fig 2, the adjustment device for synchronizing the lengths L, L'of the bellows 3,3'comprises four pulley wheels, a first pair of pulley wheels 2 being provided in the area of the active position of the mirror 10, a second pulley wheel 4 being provided on the longitudinal centre axis C of the first camera 1, on the opposite side of the camera 1 compared to the first pair of pulley wheels 2, and a third pulley wheel 6 being provided on the longitudinal centre axis C'of the second camera 1', on the opposite side of said second camera 1' compared to the first pair of pulley wheels 2. A first endless belt 8 extends around the pulley wheels 2,4,6 in the way that is shown in Fig 2. In connection therewith one part of said belt 8 is connected, in point P, to the end of the first camera 1 that faces away from the first lens 5 while the other part of said belt 8 is connected, in point P', to the end of the camera 1'that faces away from the second lens 5'.

This arrangement brings about that an adjustment of the length L'of the bellow 3'of the second camera 1', where the setting of the sharpness takes place, automatically carries out the corresponding adjustment of the length L of the bellow 3 of the first camera 1.

The length L of the first bellow 3 is thus always the same as the length L'of the second bellow 3'and the distance D+L is always of the same size as the distance D'+L'. In this connection it should be pointed out that the distances D and D'are permanently unchanged, i. e. the lenses 5 and 5'are stationary.

In connection with photographing by means of the large format camera according to the present invention the cartridge 7, loaded in the camera 1, is activated in a first step, this being done by removing the shading cover. Then the length of the second bellow 3'is adjusted in such a way that the object

M is seen in perfect sharpness through the focusing screen 9', i. e. the large format camera according to the present invention is ready for exposure. In connection with initiating the exposure the mirror 10 is displaced in its longitudinal direction to a position where the mirror 10 no longer is hit by the ray S, see Fig 2, which means that the light rays S proceed straight on, pass through the lens 5, are refracted in said lens 5 and hit the film sheet of the cartridge 7, i. e. the film is exposured. Since the displacement of the mirror 10 is very fast once the photographing has been initiated the focusing that has been set with the aid of the second camera 1'will be transferred to the film sheet of the cartridge 7. In exemplifying and non-restricting purpose it may be mentioned that the delay between the moment of initiating photographing, i. e. activation of the displacement of the mirror 10, and the exposure of the film is of the magnitude 0,2 seconds, which in conducted tests has turned out to be fully acceptable.

In Fig 3 a more concrete design of a large format camera according to the present invention is shown. A supporting structure is provided in the shape of a right-angled triangle where the catheti carry the cameras 1 and 1'respectively while the frame of the mirror 10 extends between the hypotenuse and the intersectional point of the catheti.

In Fig 4 and 5 the mirror 10, including its frame, is shown more in detail. A second end less belt 11 extends around a fourth and a fifth pulley wheel 12 and 13 respectively, said pulley wheels 12,13 being rotatably mounted in the frame. In a corresponding way a third endless belt 14 extends around a sixth and a seventh pulley wheel 15 and 16 respectively, said pulley wheels 15,16 also being rotatably mounted in the frame. As is evident from Fig 4 the second and third endless belts 11 and 14 support on one hand the mirror 10 and on the other hand a counterweight 17, whose object is to balance the movement of the mirror 10, i. e. to counteract shakings and vibrations, especially in connection with acceleration and retardation of the mirror 10.

The fifth and seventh pulley wheels 13 and 16 respectively are drivingly attached to a shaft 18 that is

rotatably mounted in the frame. An eight pulley wheel 19 is drivingly mounted on said shaft 18. Adjacent the shaft 18 an electric motor 20 is provided, a ninth pulley wheel 21 being mounted on the output shaft of the electric motor 20. An endless driving belt 22 extends between the eight pulley wheel 19 and the ninth pulley wheel 21.

When the electric motor 20 is activated the ninth pulley wheel 21 will rotate, said rotation being transferred to the eight pulley wheel 19 by means of the endless driving belt 22.

Thereby, also the shaft 18 and the fifth and seventh pulley wheels 13 and 16 respectively will rotate. The last-mentioned pulley wheels 13 and 16 drive the second and third endless belts 11 and 14 respectively, that run around the fourth and seventh pulley wheels 12 and 15 respectively and drive the mirror 10 and the counterweight 17 that are given a linear displacement in their main planes. When activating the electric motor 20, in order to displaced the mirror 10 from the position shown in Fig 4 and 5, the output shaft of the electric motor 20 wheel rotate in a direction that brings the mirror 10 to move to the left in Fig 4 and 5 while the counterweight 17 moves to the right. The electric motor 20 should be dimensioned in such a way that it may give the mirror 10 and the counterweight 17 an acceleration of at least 2g. As mentioned above this will normally bring about that the exposure of the film takes place only about 0,2 seconds after the initiation of the displacement of the mirror 10 and the counterweight 17. In connection with displacement of the mirror 10 it will move into a casing 24 of the frame. When the mirror 10 is completely inserted into the casing 24 the counterweight 17 is still inside said casing 24. As soon as the mirror 10 has left its active position, i. e. when the light rays S can pass freely through the first lens 5 of the first camera 1, the exposure is activated, which in principle means that the shutter function of the first lens 5 is activated. The activation of said shutter function may thus take place before the mirror 10 has reached its parking position within the casing 24, said activation may for instance be effected by means of a micro switch or a photo cell. In the shown the embodiment said activation is

initiated by activating a cable release (not shown) or the like, said cable release being connected to a shutter (not shown) in connection with the lens 5, see Fig 2. This brings about that exposure of the film takes place, i. e. the shutter is opened, said shutter may in a conventional way be set for different exposure times.

The electric motor 20 is operated by a suitable controlling equipment that is set in such a way that when the mirror 10 has reached inside the casing the motion of the mirror 10 and the counterweight 17 is retarded. In this connection it should be pointed out that the time from the beginning of the acceleration of the mirror 10 up to the exposure is about 0,2 seconds.

When the exposure of the film is finished the mirror 10 and the counterweight 17 are returned to the position according to Fig 4 and 5, this may possibly be effected automatically by means of the controlling equipment of the electric motor 20.

In Fig 6 and 7 it is shown how cameras of different seize, included in large format cameras, are attached to the supporting device according to Fig 3. The catheti of the supporting device are equipped with first and second quick couplings 30 and 31 respectively, that in their turn have dove-tail grooves 32,33 and 34, in which fastening means of the cameras may be received. As is evident from Fig 6 and 7 the first quick coupling 13 is equipped with two dove-tail grooves 32 and 33 respectively, of which one 32 is intended for a larger camera while the other dove-tail groove 33 is intended for a smaller camera.

Feasible Modifications of the Invention Within the scope of the invention it is feasible that the endless belts and the endless driving belt is replaced by other transmission means, e. g. chains.

The adjustment device described above in order to synchronise the lengths L, L'of the bellows 3,3'may of course be modified within the scope of the present invention.

For instance it is thus possible with cooperating gears or synchronised hydraulic cylinders.

In the embodiment described above a cable release is used to activate the shutter function of the first lens 5.

Within the scope of the present invention it is also feasible with other types of activating means. In exemplifying and non-restricting purpose electrical release of the shutter function may be mentioned.

In the described embodiment of the large format camera according to the present invention the cameras 1; 1'included in said large format camera are oriented with their longitudinal centre axes perpendicular to each other.

However, within the scope of the present invention it is feasible that this is not the case, i. e. that the angle between the centre ray SC and the mirror 10 is not equal to 45°. In this connection it is important that the second camera 1'is oriented in such a way that its longitudinal centre axis C'coincides with the centre ray SC reflected by the mirror.




 
Previous Patent: DUAL MOTOR RECIPROCATING BELT SHUTTER

Next Patent: EXPOSURE MASKS