Optics: motion pictures – With sound accompaniment – Housing and supports
Reexamination Certificate
1999-01-26
2001-07-24
Adams, Russell (Department: 2851)
Optics: motion pictures
With sound accompaniment
Housing and supports
C352S034000, C352S139000, C352S140000
Reexamination Certificate
active
06266124
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a device for focusing a film frame.
BACKGROUND OF THE INVENTION
For setting the iris diaphragm opening, picture definition and focal width of a camera lens, lens rings are mounted on the lens housing. By turning the lens rings, the lens system is linearly displaced through a gearing and, thus, the picture definition and focal width of the camera lens are changed. The manual adjustment of the iris diaphragm opening, focus and focal width (zoom) of the camera lens on the lens rings provided for this purpose is difficult for the cameraman. This is particularly difficult when viewing, at the same time, the image through the viewfinder eyepiece. Making reproducible setting of certain focal widths, focus values and iris diaphragm openings is linked with considerable difficulties and, further, pre-programming predeterminable values is not possible.
For a simpler and more reliable setting of the lens rings, drive units are known which are fixed on iris rods connected to the camera housing and each transferring, through a pinion, a torque to an external gearing of the lens rings so as to carry out the adjustment of the lens rings in this way. With these additional drive units, the operation is easier for the cameraman and there is the possibility of connecting the drive units to a control device or to set pre-programmable values for the iris diaphragm opening, the image definition and focal width of the camera lens.
Converting the rotary movement of the lens rings into the linear displacement of the lens system of the camera lens requires, however, a certain play in order to allow easy adjustability. In the same way, a certain play between the pinion of the drive unit and the external teething of the lens ring is unavoidable, which is a problem particularly when focusing where the slightest displacements of the camera lens can lead to the image being out of focus. Less of a problem is setting the iris diaphragm opening and the focal width, because the image detail and the depth of focus can be easily corrected and even slightly inaccurate settings need not lead to the shots becoming unusable.
In many cases the use of an optically optimized lens with fixed focal width is possible wherein only the adjustment of the iris diaphragm opening and image definition is required.
From U.S. Pat. No. 4,437,552, a movie film camera is known having a shutter, film transport mechanism and a focusing device which are driven by a common drive motor through a spring coupling. The camera lens is connected to a displacement device for the translatory displacement of the camera lens. The device consists of a connecting rod which is mounted in fixed guides and is connected to a cam disc. The cam disc controls the translation movement of the camera lens and is connected to a worm gear connected to the spring coupling. The displacement device is additionally connected to a device for automatically focusing the film pictures.
From U.S. Pat. No. 3,250,197 a focusing device for an image converter connected to a picture carrier is known which consists of a device for the translatory displacement of the distance between a lens assembly connected to the image converter and the picture carrier.
From DE A 342 40 14 a stationary film camera is known wherein to focus the picture it is not the lens, but the film gate with the film window which is moved in translation along the optical axis of the stationary film camera. The translatory displacement is undertaken by several spindles set parallel to the optical axis and engaging in threaded bores of the film gate. Through a synchronous turning of the spindles, the film gate is moved in translation in the direction of the optical axis until, in dependence on an automatic distance meter, an electromagnetically operated locking means drops into the gearing. After film exposure and during the next film transport step, the gearing is returned with the film gate back to the starting position.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a precise and reproducible focusing device which can be used for automatic image definition adjustment without any lens ring or drive unit attached to the camera lens. A further object is to connect this focusing device to a device for blocking or insulating the noises emanating from a camera mechanism of a movie film camera.
The solution according to the invention provides, firstly, a device for focusing a film image in a movie film camera which allows a precise setting of the image definition and is particularly suitable for automatic focusing and integration of the image definition setting in the automatic operation of a movie film camera and, secondly, provides a high noise deadening or noise insulation of the noises emanating from the camera mechanism in the case of a movie film camera which consists of an outer camera housing and an inner camera which are connected together through controllable connecting elements.
The noise-insulating connecting elements which are mounted to reduce or insulate the noise between the film window and the lens carrier are thereby additionally used for adjusting the focus so that no additional structural measures are required in the camera housing of the movie film camera because the corresponding control of the connecting elements is integrated in the control and regulating electronics of the movie film camera.
The solution according to the invention is particularly suitable for using a camera lens with a fixed lens assembly, that is, for a camera lens of predetermined focal width wherein, either a setting of the iris diaphragm opening can be executed outside of the camera lens or an iris diaphragm is not provided.
The displacement device preferably contains a guide device running parallel to the optical axis of the movie film camera and consists of a guide rail and a guide slide which is connected to the displacement device.
The displacement device preferably consists of an electromagnetic, electrostrictive, magnetostrictive or piezoelectric converter whose length can be changed by means of a control switch.
The change in the distance between the lens plane and image plane can be selectively carried out by a device for the translatory displacement of the lens carrier and/or camera lens along the optical axis of the movie film camera or by a device for the translatory displacement of the film window along the optical axis of the movie film camera.
The translatory displacement of the camera lens along the optical axis of the movie film camera is particularly suitable for integration of the displacement device in the camera housing and thus, in particular, for use in new movie film cameras.
For the translatory displacement of the lens carrier along the optical axis of the movie film camera, an adapter can advantageously be mounted between the camera lens and lens carrier. The adapter has an assembly for the translatory displacement of the distance between a lens fixing and connection with the lens carrier. This assembly is particularly suitable for equipping existing movie film cameras having a fixed connection of the lens carrier on the camera housing of the movie film camera.
A translatory displacement of the film window makes it possible to shift the image plane for adjusting the image definition without internal or external displacement of the camera lens. The use of a camera lens of fixed focal width is thereby particularly possible with optimum matching of the lens system so that no optical losses occur through the displacement or displaceability of the camera lens.
Also, the use of existing lenses provided with one lens ring for setting the image definition is possible, utilizing the advantages according to the invention in that, for example, a fixed focal value is set and this setting is fixed.
REFERENCES:
patent: 3250197 (1966-05-01), Fladlien et al.
patent: 3584559 (1971-06-01), Levin
patent: 4437552 (1984-03-01), Toyama
patent: 4536066 (1985-08-01), Bauer
patent: 5037195 (1991-08-01), Clairmont et al.
patent: 5225941 (199
Trauninger Walter
Wallner Kurt
Adams Russell
Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
Christie Parker & Hale LLP
Fuller Rodney
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