Lens filters

Abstract

To provide a lens filter capable of suppressing the occurrence of light pollution and emphasizing point light sources such as stars. [Solution] The lens filter 10 is made of colored glass 1 and has a pattern 4 with a diffusion effect on at least the front surface 2. By using this lens filter 10, it is possible to prevent light pollution that occurs during photography, suppress color casts, make the night sky look clear and contrasty, adjust the color to suit the color of the night sky, clearly express the brightness of stars, and emphasize point light sources such as stars.

Description

[Technical Field]

[0001] The present invention relates to a lens filter. [Background technology]

[0002] A filter unit that can be attached to an imaging device has been disclosed (for example, Patent Document 1). A typical filter unit includes a polarizing filter, an ND filter, a lens protection filter, etc. However, depending on the subject being photographed, a light pollution cut filter for cutting out light pollution may be placed in the filter unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-189451 Summary of the Invention [Problem to be solved by the invention]

[0004] Light pollution filters are primarily used for night photography, suppressing the color cast caused by city lights and allowing you to capture photos with clear, contrasting night skies and natural color tones. They are particularly effective when photographing mercury vapor lamps used in warehouses and factories, or sodium vapor lamps used on highways. Because these lights have a significant impact over long distances, light pollution filters are valuable and a standard filter for astrophotography. However, using a light pollution filter alone can make it difficult to clearly portray the brightness of stars, such as first- and third-magnitude stars, or to emphasize point light sources like stars.

[0005] The problem that this invention aims to solve is a lens filter that can suppress color cast, make the night sky look clear and contrasty, adjust the color to suit the color of the night sky, clearly express the brightness of stars, and emphasize point light sources such as stars.The object of this invention is to provide a lens filter that can eliminate light pollution during photography and emphasize point light sources such as stars. [Means for solving the problem]

[0006] The lens filter according to the present invention is made of colored glass and has a pattern that has a diffusing effect formed on at least one surface.

[0007] The lens filter according to the present invention is characterized in that the pattern is formed by etching.

[0008] The lens filter of the present invention is characterized in that the colored glass has a maximum absorption wavelength range from 550 nm to 630 nm.

[0009] The lens filter of the present invention is characterized in that the area of ​​the patterned design is 50% to 100% of the area of ​​one side of the colored glass. [Effects of the Invention]

[0010] The lens filter of this invention is made of colored glass with a diffusion pattern on at least one surface, which prevents light pollution, reduces color casts, and creates a clear, contrasting night sky, enhancing the color of the night sky, making the brightness of stars more easily visible, and emphasizing point light sources such as stars. [Brief explanation of the drawings]

[0011] [Figure 1]1A and 1B are diagrams illustrating a lens filter according to an embodiment of the present invention, in which (a) is a perspective view and (b) is a side view. [Figure 2] 1A and 1B are diagrams illustrating lens filters with different etching surface areas according to an embodiment of the present invention. [Figure 3] Photographs taken using a lens filter according to an embodiment of the present invention are shown in (a) and (b), respectively, with and without the lens filter attached. DETAILED DESCRIPTION OF THE INVENTION

[0012] The lens filter of the present invention is made of colored glass and has a pattern with a diffusion effect formed on at least one surface. The pattern is formed by etching, and the colored glass of the lens filter of the present invention has a maximum absorption wavelength range of 550 nm to 630 nm. Furthermore, the lens filter of the present invention can have an etched surface area that accounts for 50% to 100% of the area of ​​one surface of the colored glass. The lens filter of the present invention can prevent light pollution, reduce color cast, make the night sky look clear and contrasty, adjust the color to suit the color of the night sky, clearly show the brightness of stars, and emphasize point light sources such as stars.

[0013] In this embodiment, a lens filter 10 used in a digital single-lens reflex camera will be described with reference to FIGS.

[0014] As shown in Figure 1(a), the lens filter 10 is made of circular colored glass 1, and has the property of absorbing light that passes through it, attenuating the amount of light and reducing the light transmittance. Colored glass is glass to which coloring components have been added, and is colored by various transition metal ions, rare earth ions, colored colloids, etc. The colored glass 1 preferably has a maximum absorption wavelength range of 550 nm to 630 nm, and the lens filter 10 has a thickness of, for example, 1 mm to 3 mm.

[0015] As shown in FIG. 1(b), the lens filter 10 has a pattern 4 with a diffusion effect formed by etching the entire front surface (one surface) 2 of the colored glass 1, while the back surface 3 (the other surface) is not etched. The etching is performed by photolithography. Note that the method for forming the pattern 4 with a diffusion effect is not limited to etching, and it can be formed appropriately by any known method. The thickness of the etched layer is, for example, 150 nm to 200 nm. The thickness of the etched layer can be appropriately changed to obtain a desired diffusion effect.

[0016] The lens filter 10 is placed so that the etched surface (pattern) 4 faces the subject. The lens filter 10 is used by being placed in front of the lens, behind the lens, or in the middle of the lens.

[0017] Next, the effects of the lens filter according to this embodiment will be described.

[0018] FIG. 3(a) shows a night scene photographed using the lens filter 10 according to this embodiment, and FIG. 3(b) shows a night scene photographed without using the lens filter 10. In the photo taken without the lens filter 10, it is clear that light pollution has occurred. The effects of light pollution are particularly noticeable near the boundary between the mountains and the starry sky. In addition, the brightness of the stars is difficult to discern, and the starlight is not emphasized (Figure 3(b)). On the other hand, when a photograph is taken with the lens filter 10 according to this embodiment attached, light pollution is suppressed, color cast is reduced, the night sky appears clear with good contrast, and the colors are adjusted to suit the color of the night sky (FIG. 3(a)). Furthermore, it was found that the light of stars, which are point light sources, is emphasized, and the brightness of the stars is clearly expressed.

[0019] The lens filter 10 according to this embodiment is made of colored glass and can absorb light of the desired wavelength. Therefore, by using this lens filter 10, it is possible to prevent light pollution, suppress color casts, make the night sky appear clear and contrasty, and adjust the color to suit the color of the night sky. Furthermore, the lens filter 10 according to this embodiment has an etched surface 4 formed on at least one side, which adjusts the diffusion of light. Therefore, by using the lens filter 10, it is possible to clearly express the brightness of stars and emphasize point light sources such as stars.

[0020] To achieve the same effect, multiple lens filters must be used, which requires checking the position of the filters and takes time, making installation time-consuming and cumbersome. The lens filter 10 of this embodiment is made of a single piece of colored glass, which prevents it from being installed in the wrong position and eliminates the hassle and hassle that occurs when installing multiple lens filters.

[0021] When taking a photograph with multiple lens filters attached, there is a risk of vignetting occurring on all sides of the photograph, but the lens filter 10 according to this embodiment is made up of a single piece of colored glass 1 and does not use multiple lens filters, so vignetting is prevented. Furthermore, by using this lens filter 10, flare ghosts can also be prevented.

[0022] As described above, the lens filter 10 of this embodiment reduces color cast, makes the night sky look more contrasty, adjusts the color to resemble a night sky, clearly expresses the brightness of stars, and emphasizes point light sources such as stars, while also eliminating the hassle of installation and the occurrence of vignetting.

[0023] The lens filter 10 according to this embodiment can also have an etched surface 4 formed on the entirety of both the front surface 2 and the back surface 3 of the colored glass 1. Additionally, the area of ​​the etched surface 4 of the colored glass 1 can be changed. Specifically, the area of ​​the etched surface 4 can be set to 50% to 100% of the area of ​​the front surface 2 (back surface 3) of the colored glass 1. As shown in FIG. 2, the etched surface 4 is formed on one side (for example, the upper side) of the colored glass 1. By using this lens filter 10, when the upper side of the scene being photographed is a starry sky and the lower side is earth, light pollution can be prevented while the starlight in the starry sky is more emphasized, making it possible to take a photograph in which the brightness of the stars is clearly visible.

[0024] The present embodiment has been described above, but it is possible to select and discard the configurations given in the above embodiment, or to change them to other configurations as appropriate, as long as they do not deviate from the spirit of the present invention.

[0025] For example, while the present embodiment has been described with respect to a lens filter using colored glass, a transparent glass substrate that has been etched can also be used as a lens filter. Furthermore, the lens filter of the present invention can be made by combining multiple sheets of colored glass, as long as it prevents light pollution and has the effect of diffusing light. For example, colored glass sheets can be bonded together via an adhesive layer containing fine powder and used as a lens filter. [Explanation of symbols]

[0026] 1. Colored glass 2 Front side (one side) 3 Back side (other side) 4 Etched surface (pattern) 10 Lens Filters

Claims

1. A lens filter made of colored glass, A pattern having a diffusion effect is formed on at least one surface. A lens filter characterized by:

2. The pattern is formed by etching.

2. The lens filter according to claim 1.

3. The colored glass has a maximum absorption wavelength range from 550 nm to 630 nm.

3. The lens filter according to claim 1 or claim 2.

4. The area of ​​the patterned design relative to the area of ​​the one surface of the colored glass is 50% to 100%.

3. The lens filter according to claim 1 or claim 2.

Images