Variable-effect light filtering device
Through the combination of filters and apertures of variable-effect filter devices, the flexible adjustment of lens imaging effects in the film industry is solved, and the rapid and uniform image changes are achieved. It is suitable for multi-focus lenses, reducing cost and complexity.
Patent Information
- Application Number
- CN202380087143.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-19
- Filing Date
- 2023-12-18
- Publication Date
- 2025-07-25
AI Technical Summary
The prior art is difficult to flexibly and simply change the image imaging effect of lens formation in the film industry, especially in the mid-frequency pattern, the contrast selection is limited by lens selection, and there are problems of unevenness and texture presentation of diffusion filters and lens movement methods.
Variable effect filtering device is adopted, including a filter and an aperture. The filter has a central area and an peripheral area. The aperture can be adjusted to change the enterable part of the filter area, achieving flexible adjustment of the filter effect.
It realizes rapid change of image imaging effects in a short time, avoids unevenness and texture presentation, and is suitable for lens series with different focal lengths, which is cheap and easy to manufacture.
Smart Images
Figure CN120380384A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a variable-effect filter device. The present invention also relates to an assembly including a photographic objective and such a filter device. The present invention also relates to a method of using such a filter device to change the imaging effect of an image.
[0002] The present invention relates to the film industry and generally to photographic imaging. Background Art
[0003] Specifically, in the film industry, cinematographers select their lenses based on the film to be shot and their preference for a lens series with a lighting method that they consider suitable for themselves. In fact, some lenses may be softer, in other words, these lenses have lower contrast at medium-frequency patterns (5 cy / mm to 50 cy / mm) and good resolution (>150 cy / mm) for S35 to full-frame (FullFrame, FF) sensors. On the other hand, some other lenses are called hard-tone lenses because of their good quality (or modulation transfer function) at medium frequencies. Therefore, the choice of achieving a specific contrast (partially) depends on the choice of lens.
[0004] However, this modularity is limited by the requirement that for a given sequence, a series of focal lengths that can achieve the same performance are needed.
[0005] A diffuser filter can be placed in front of or behind the lens. However, this setting has the risk of presenting the texture of the diffuser in the bokeh (background blur) of the image.
[0006] In addition, the lens can also be moved by means of spherical aberration to reduce the contrast. However, this imaging effect is different from that of the diffuser filter and is non-uniform across the entire field of view.
[0007] Therefore, there is a need for a device that can change the imaging effect of an image formed by a lens in a simple and flexible manner at any time. Summary of the Invention
[0008] To this end, the object of the present specification is to provide a variable-effect filter device, which includes:
[0009] a. A filter having a working surface including a central region and a peripheral region surrounding the central region, the filter having predefined optical properties in a region called the filter region, the filter region being the central region or the peripheral region or the entire working surface; and
[0010] b. An aperture having an opening that is adjustable from a fully open state to a maximum closed state, the aperture being disposed relative to the filter such that the fully open state of the aperture corresponds to the working surface of the filter, and such that adjustment of the opening of the aperture changes the accessible portion of the filtering region or the accessible portion of another region of the working surface (23), thereby enabling the filtering effect to be changed.
[0011] According to a particular embodiment, the device comprises one or more of the following features, individually or in any technically possible combination:
[0012] The filtering region is a central region or a peripheral region, and the predefined optical properties are uniform within the filtering region.
[0013] The predefined optical properties exhibit a progressive radial variation within the filtering region.
[0014] The fully open state of the aperture defines the peripheral region of the filter.
[0015] The filtering region has substantially the same shape as the opening of the aperture, except for an approximate scaling difference.
[0016] The shape of the central region is selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical, and star-shaped.
[0017] The predefined optical properties are selected from one of the following properties: diffusing property, polarization property, chromaticity property, wavefront aberration property, transparency property, and a combination of at least two of the foregoing properties.
[0018] The filtering region is a central region or a peripheral region, and the working surface of the filter includes at least one intermediate region that surrounds the central region and is surrounded by the peripheral region, and the at least one intermediate region includes a progressive radial variation of the predefined optical properties between the central region and the peripheral region.
[0019] The aperture is an iris aperture.
[0020] This specification also relates to a component that includes:
[0021] a. A taking objective lens; and
[0022] b. A filtering device that is disposed generally at the diaphragm of the taking objective lens, thereby enabling the imaging effect of the image formed by the taking objective lens to be changed.
[0023] This specification also relates to a method for changing the imaging effect of an image formed by a taking objective lens, the method including:
[0024] a. Disposing the filtering device as described above generally at the diaphragm of the taking objective lens; and
[0025] b. Adjust the aperture opening to change the accessible portion of the light filtering area or another area of the working surface, thereby changing the light filtering effect and enabling the change of the imaging effect of the image formed by the photographing objective lens. Description of the Drawings
[0026] Other features and advantages of the present invention will become apparent from the following description of embodiments of the present invention given by way of example only and with reference to the following drawings, which are:
[0027] Figure 1 A schematic diagram of an assembly including a photographing objective lens and a light filtering device;
[0028] Figure 2 A schematic diagram of a light filtering device according to a first embodiment, in which the aperture of the light filtering device is in a fully open state;
[0029] Figure 3 For Figure 2 A schematic diagram of the light filtering device shown, in which the aperture of the light filtering device is in an intermediate opening state;
[0030] Figure 4 For Figure 2 A schematic diagram of the light filtering device shown, in which the aperture of the light filtering device is in another intermediate opening state;
[0031] Figure 5 A schematic diagram of a light filtering device according to a second embodiment, in which the aperture of the light filtering device is in an intermediate opening state;
[0032] Figure 6 For Figure 5 A schematic diagram of the light filtering device shown, in which the aperture of the light filtering device is in another intermediate opening state; and
[0033] Figure 7 A schematic diagram of a light filtering device according to a third embodiment, in which the light filtering area extends over the entire working surface of the light filter. Detailed Embodiments
[0034] Figure 1 The photographing objective lens 10 and the light filtering device 12 are shown.
[0035] The photographing objective lens 10 is capable of forming an image of a scene on a sensor. For example, the photographing objective lens 10 is a lens or a zoom lens of a camera or a movie camera. The photographing objective lens 10 generally includes at least one lens and is generally a set of lenses.
[0036] The light filtering device 12 is capable of producing a variable light filtering effect. The term "variable" means that the light filtering varies according to the configuration (adjustment) of the light filtering device 12, and this adjustment can be easily completed in less than one second.
[0037] The filter device 12 is generally positioned at the aperture of the photographing objective lens 10 (as Figure 1 shown) to change the imaging effect of the image formed by the photographing objective lens 10. The term "generally" means "approximately", or, more precisely, the distance from the aperture is less than a predetermined distance. For example, the predetermined distance is equal to 2 mm.
[0038] The filter device 12 includes a filter 20 and an aperture 22.
[0039] The filter 20 is a planar optical filter. For example, the filter 20 is made of glass or plastic material.
[0040] As Figures 2 to 6 shown in the example of C , the filter 20 includes a working surface 23, which includes a central region Z C and a peripheral region Z P surrounding the central region Z. Figures 2 to 6 In the example of
[0041] , the working surface 23 extends over the entire surface of the filter 20. Alternatively, the working surface 23 only extends over a part of the filter 20. C Preferably, the surface area of the central region Z P is at least 30% of the surface area of the peripheral region Z.
[0042] Preferably, the shape of the central region Z C is selected according to the desired imaging effect. For example, the shape of the central region Z C is selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical, and star-shaped. More generally, the shape of the central region Z C is any shape that can be formed by adjusting an aperture (such as an iris aperture).
[0043] In Figures 2 to 6 the example of C , the central region Z is circular.
[0044] The filter 20 has predefined optical properties only in one of the central region Z C and the peripheral region Z P , which is called the filtering region. Therefore, the other region exhibits different optical properties.
[0045] For example, in Figures 2 to 4 the embodiment of C , the filtering region is the central region Z Figure 5 and Figure 6 in the embodiment of P , the filtering region is the peripheral region Z.
[0046] Preferably, the predefined optical property is selected from one of the following properties: diffusion property (diffusion filter region and non-diffusion region), polarization property (polarization filter region and non-polarization region), chromaticity property (colored filter region and colorless region), wavefront aberration property, transparency property (transparent filter region and opaque or partially transparent region), opacity property (opaque or partially transparent filter region and another transparent region), and a combination of at least two of the aforementioned properties. The value of the optical property is adjusted according to the desired imaging effect.
[0047] In an exemplary embodiment, the predefined optical property is uniform within the filter region.
[0048] Alternatively, the predefined optical property exhibits a radial variation within the filter region. Thus, the variation is gradual and continuous radially. For example, in the case of the diffusion property, the diffusion continuously increases from the center of the filter region towards the periphery of the filter region, or vice versa.
[0049] In an optional embodiment, the filter 20 further includes an intermediate region that surrounds the central region Z C and is surrounded by the peripheral region Z P The predefined optical property of the intermediate region varies gradually (radially) between the central region Z C and the peripheral region Z P This can avoid a discontinuous change in the optical property between the central region Z C and the peripheral region Z P especially when the optical property is uniform within the filter region.
[0050] The aperture 22 has an opening that can be adjusted from the fully open state to the maximum closed state of the adjustable aperture 22.
[0051] Preferably, the opening is continuously adjusted between the fully open state and the maximum closed state of the aperture 22. For example, the adjustment is performed by an adjustment mechanism. For example, the aperture 22 is an iris aperture.
[0052] The aperture 22 is arranged relative to the filter 20 such that:
[0053] The fully open state of the aperture corresponds to the working surface 23 of the filter 20; and
[0054] Adjusting the opening of the aperture 22 changes the accessible portion of the filter region or the accessible portion of another region of the working surface, thereby enabling the change of the filtering effect. In other words, it changes the accessible ratio of the filter region relative to another region (i.e., the ratio between the unobstructed portion of the filter region and the unobstructed portion of another region). "Accessible" means that the light flux can enter or is "useful".
[0055] Preferably, during the opening of the aperture 22, the accessible part of the filter area or the accessible part of another area of the working surface 23 is changed radially. In Figures 2 to 6 the example of C , both the accessible part of the filter area and the accessible part of another area can be changed radially. The term "radially" means within the plane of the filter 20 and perpendicular to an axis that generally passes through the center of the central area Z C and is generally perpendicular to the plane of the filter 20. When the filter device 12 is generally positioned at the aperture of the imaging objective 10, this axis is the optical axis of the imaging objective 10. In this case, the filter device 12 is arranged relative to the imaging objective 10, that is, the filter 20 is generally arranged perpendicular to the optical axis of the imaging objective 10, and the central area Z
[0056] Preferably, the opening of the aperture 22 is centered on the center of the central area Z C .
[0057] Preferably, the fully open state of the aperture 22 defines the peripheral area Z P of the filter 20.
[0058] Preferably, the maximum closed state of the aperture 22 completely obscures the central area Z C and the peripheral area Z P of the filter 20.
[0059] Preferably, the central area Z C and the opening of the aperture 22 have substantially the same shape (except for an approximate scaling difference). In Figures 2 to 6 the example of C , the central area Z
[0060] and the opening are circular.
[0061] Now, a method for changing the imaging effect of the image formed by the imaging objective 10 via the filter device 12 will be described. C The filter device 12 is arranged relative to the imaging objective 10 so that it is generally located at the aperture of the imaging objective 10. Preferably, the position of the filter device 12 is such that the optical axis of the imaging objective 10 passes through the center of the central area Z
[0062] Then, the opening of the aperture 22 is adjusted so as to radially change the accessible part of the filtering zone or the accessible part of another zone of the working surface 23, thereby achieving a change in the imaging effect of the image formed by the photographing objective 10. Typically, when this characteristic is a diffusing characteristic, depending on the opening of the aperture 22, the image will appear more or less blurred ("soft focus" effect). Thus, by opening or closing the aperture 22, for example, by simply rotating it one full turn, the effect of the image to be formed by the objective can be significantly changed.
[0063] In Figures 2 to 4 the embodiment, only the central zone Z C has a diffusing characteristic. This characteristic can change the contrast of the image (the more light passes through the diffusing zone, the softer the image). In Figure 2 the case, the aperture 22 is fully open, which means that about 14% of the diaphragm is diffused. In Figure 3 it, the aperture 22 is in an intermediate opening state (T3.6), and the peripheral zone Z P is still partially visible, which means that about 40% of the diaphragm is diffused. In Figure 4 it, the aperture 22 is in an intermediate opening state (T5.6), and the peripheral zone Z P is completely blocked, which means that 100% of the diaphragm is diffused.
[0064] In Figure 5 and Figure 6 the embodiment, only the peripheral zone Z P exhibits a diffusing characteristic. In Figure 5 the case shown, the aperture 22 is at an intermediate opening, and the peripheral zone Z P is still partially visible, which means that the diffusion of the diaphragm is obvious. In Figure 6 the case shown, the aperture 22 completely blocks the peripheral zone Z P , which means that the diaphragm is not diffused.
[0065] Therefore, the filtering device 12 can change the imaging effect of the image formed by the photographing objective 10 in a simple and rapid manner. The adjustment is carried out outside the objective and can be performed at any time, for example, by rotating the aperture 22 to open or close it.
[0066] The production cost of this optical filter is low and it is easy to manufacture. For example, in the case of diffusion, the filter can consist of a plastic film (such as a Mitchell filter) pasted between two plates, or of a frosted plate, a holographic diffuser, a pasted grid in the required surface, or any other diffusion principle.
[0067] In addition, it should be noted that the present invention can achieve, under the same aperture opening 22, for objective lenses of the same series but different focal lengths, as long as the size of the filter 20 is appropriate (especially the accessible part of the central region Z C and the peripheral region Z P ), the same filtering effect can be obtained.
[0068] Although the examples in the specification highlight the diffusing characteristics, the present invention is applicable to all types of optical characteristics and can change the imaging effect of the image formed by the objective lens according to the opening of the aperture.
[0069] In addition, it should be noted that the filtering device is not limited to the case where the filtering region extends only in one of the central region Z C or the peripheral region Z P . In fact, in an alternative embodiment shown in Figure 7 , the filtering region extends over the entire working surface 23 of the filter 20. In this case, the adjustment of the aperture 22 opening only changes the accessible part of the filtering region (rather than another region of the working surface 23, because the filtering region occupies the entire working surface 23). Preferably, the predefined optical characteristics exhibit a continuous progressive change (radially) within the filtering region. For example, in the case of diffusing characteristics, the diffusion continuously increases from the center (central region) of the working surface 23 to the periphery (peripheral region) of the working surface 23, or vice versa. The other features previously described, especially Figures 2 to 6 's implementation manner, is also applicable to this additional embodiment.
[0070] More generally, those skilled in the art should understand that the previously described embodiments and alternatives can be combined with each other on the premise of technical compatibility.
Claims
1. A variable-effect filter device (12), comprising: Filter (20) having a working surface (23) including a central region (Z C ) and a peripheral region (Z C ) surrounding said central region (Z P ), said filter (20) having predefined optical properties in a region called the filtering region, said filtering region being said central region (Z C ) or said peripheral region (Z P ) or the entire said working surface (23); and an aperture (22) having an opening that can be adjusted from a fully open state to a maximum closed state of the aperture (22), the aperture (22) being disposed relative to the filter (20) such that the fully open state of the aperture (22) corresponds to the working surface (23) of the filter (20), and such that adjustment of the opening of the aperture (22) changes an accessible portion of the filter region or an accessible portion of another region of the working surface (23), thereby being able to change the filtering effect.
2. The device (12) according to claim 1, characterized in that, The filter region is the central region (Z C ) or the peripheral region (Z P ), and the predefined optical property is uniform within the filter region.
3. The device (12) according to claim 1, characterized in that, The predefined optical properties exhibit a progressive radial variation within the filter region.
4. The device (12) according to any one of claims 1 to 3, characterized in that, The fully open state of the aperture (22) defines the peripheral region (Z P ) of the filter (20).
5. The device (12) according to any one of claims 1 to 4, characterized in that, The filter region and the opening of the aperture (22) have substantially the same shape, except for an approximate scaling difference.
6. The device (12) according to any one of claims 1 to 5, characterized in that, The central region (Z C ) has a shape selected from one of the following shapes: circular, square, rectangular, parallelepiped, triangular, elliptical, and star-shaped.
7. The device (12) according to any one of claims 1 to 6, characterized in that, The predefined optical properties are selected from one of the following properties: diffusion property, polarization property, chromaticity property, wavefront aberration property, transparency property, and a combination of at least two of the foregoing properties.
8. The device (12) according to any one of claims 1 to 7, characterized in that, The light filtering region is the central region (Z C ) or the peripheral region (Z P ), the working surface (23) of the filter (20) includes at least one intermediate region that surrounds the central region (Z C ) and is surrounded by the peripheral region (Z P ), and the at least one intermediate region includes a progressive radial variation of the predefined optical properties between the central region (Z C ) and the peripheral region (Z P ).
9. The device (12) according to any one of claims 1 to 8, wherein, The aperture (22) is an iris aperture.
10. An assembly, comprising: a. An imaging objective (10); and b. A filter device (12) according to any one of claims 1 to 9, the device (12) being positioned generally at the diaphragm of the imaging objective (10), thereby being able to change the imaging effect of an image formed by the imaging objective (10).
11. A method for changing the imaging effect of an image formed by an imaging objective (10), the method comprising: a. Positioning a filter device (12) according to any one of claims 1 to 10 generally at the diaphragm of the imaging objective (10); and b. Adjusting the opening of the aperture (22) to change an accessible portion of the filter region or an accessible portion of another region of the working surface (23) to change the filtering effect, thereby being able to change the imaging effect of an image formed by the imaging objective (10).