A full-frame large-aperture mirrorless camera lens with fast focusing and its imaging method

Abstract

The present invention relates to a fast-focusing, full-frame, large-aperture micro-single lens and an imaging method thereof. The lens comprises an optical system comprising a first lens, a cemented lens group, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, arranged in sequence from left to right along an incident light path. The cemented lens group comprises a second lens and a third lens. By rationally allocating the focal power, surface shape, center thickness, and on-axis distance between each lens, the present invention achieves fast focusing while meeting the imaging performance requirements of a full-frame, large-aperture lens.

Description

Technical Field

[0001] The present invention relates to a fast-focusing full-frame large-aperture micro single lens and an imaging method thereof. Background Art

[0002] The term "micro-single" has two meanings. "Micro" refers to miniature and compact, while "single" refers to an interchangeable single-lens camera. "Micro-single" cameras are positioned as a crossover between digital SLRs and compact cameras. They utilize the same sensor specifications as SLRs, but eliminate the optical viewfinder components found in SLRs. The lack of a prism and mirror significantly reduces the distance between the lens mount and the sensor, allowing for more diverse body designs and a more compact body than a SLR, while maintaining the same image quality.

[0003] With the advancement of technology, the demand for large-aperture lenses in the mirrorless camera market has become increasingly strong. This is because a large aperture often means more light entering and a wider field of view, which in turn represents higher image quality. However, as the aperture increases, the requirements for shutter speed and focus become increasingly stringent. Therefore, large-aperture photographic lenses that can focus quickly are a hot topic in the market. Summary of the Invention

[0004] The present invention improves the above-mentioned problem. That is, the technical problem to be solved by the present invention is to provide a fast-focusing full-frame large-aperture micro-single lens and an imaging method thereof, which uses a single lens for fast focusing while achieving clear full-frame large-aperture imaging.

[0005] The present invention is constructed as follows: it includes an optical system of a lens, which includes a first lens, a cemented lens group, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens, which are arranged in sequence from left to right along the incident light path of the light. The cemented lens group includes a second lens and a third lens, the first lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus convex positive lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the sixth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the seventh lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; and the eighth lens is a meniscus concave negative lens, whose object side surface is concave and whose image side surface is convex.

[0006] Furthermore, the air gap between the first lens and the second lens is 0.1-0.5 mm; the second lens and the third lens are a cemented lens group, and the air gap is 0 mm; the air gap between the third lens and the aperture is 3.5-4.0 mm; the air gap between the aperture and the fourth lens is 1.1-1.5 mm; the air gap between the fourth lens and the fifth lens is 3.1-3.5 mm; the air gap between the fifth lens and the sixth lens is 0.0-0.5 mm; the air gap between the sixth lens and the seventh lens is 22.5-23.0 mm; and the air gap between the seventh lens and the eighth lens is 21.5-22.0 mm.

[0007] Furthermore, the focal length of the optical system is The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are respectively ,in and Meet the following ratios: .

[0008] Furthermore, the first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the sixth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0009] Furthermore, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤1.5.

[0010] Furthermore, the image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.0.

[0011] Furthermore, the aperture of the optical system is located behind the third lens, and a filter is provided on the rear side of the eighth lens.

[0012] Furthermore, the F number of the optical system is ≤1.8.

[0013] Furthermore, in the imaging method of the fast-focusing full-frame large-aperture micro-single lens, light is formed after passing through the first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens from left to right.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. This lens offers high image clarity, a large aperture of F≤1.8, and excellent focusing capabilities, enabling handheld shooting at night and in low-light conditions.

[0016] 2. Through the reasonable matching of optical lenses, the system structure is compact and reasonable, easy to assemble, with low tolerance sensitivity, and more suitable for large-scale high-yield production;

[0017] 3. All glass spherical lenses are used, which can adapt to the environment and reduce costs to a certain extent;

[0018] 4. Able to make good compensation for focal plane displacement at high and low temperatures, and have adaptability to complex environments;

[0019] 5. Corrected axial chromatic aberration, vertical chromatic aberration and high-order chromatic aberration to ensure high imaging quality of the imaging system;

[0020] 6. When focusing, a single lens L6 movement is adopted, which greatly improves the focusing efficiency and thus achieves fast focusing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the optical structure of an embodiment of the present invention;

[0022] Figure 2 This is a full-band axial chromatic aberration diagram of an embodiment of the present invention;

[0023] Figure 3 This is a vertical axis chromatic aberration diagram for the entire working band of an embodiment of the present invention;

[0024] Figure 4 1 is a field curvature distortion diagram of the full working band of an embodiment of the present invention;

[0025] In the figure: STO-aperture; L1-first lens; L2-second lens; L3-third lens; L4-fourth lens; L5-fifth lens; L6-sixth lens; L7-seventh lens; L8-eighth lens; L9-equivalent glass plate; IMA-imaging surface. DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1: Figure 1-4 As shown, in this embodiment, a fast-focusing full-frame large-aperture micro-single lens is provided, including an optical system of the lens, the optical system including a first lens, a cemented lens group, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens arranged in sequence from left to right along the incident light path of the light, the cemented lens group including a second lens and a third lens; wherein the optical power of each lens adopts a positive and negative combination, which greatly reduces optical aberrations such as spherical aberration. The second lens and the third lens form an achromatic double cemented lens. Reasonable lens matching enables the optical system to achieve fast focusing and full-frame large-aperture imaging at the same time, and by correcting the on-axis and off-axis aberrations well, the lens has good imaging quality, such as Figures 2 to 4 shown.

[0028] Without considering the backcurvature caused by the aspheric coefficient, the above-mentioned first lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus convex positive lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the sixth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the seventh lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the eighth lens is a meniscus concave negative lens, whose object side surface is concave and whose image side surface is convex; the lenses are made of glass material and the system is an all-glass spherical lens system.

[0029] In this embodiment, the air gap between the first and second lenses is 0.1-0.5 mm; the second and third lenses form a cemented lens group, and the air gap is 0 mm; the air gap between the third lens and the aperture is 3.5-4.0 mm; the air gap between the aperture and the fourth lens is 1.1-1.5 mm; the air gap between the fourth and fifth lenses is 3.1-3.5 mm; the air gap between the fifth and sixth lenses is 0.0-0.5 mm; the air gap between the sixth and seventh lenses is 22.5-23.0 mm; and the air gap between the seventh and eighth lenses is 21.5-22.0 mm.

[0030] In this embodiment, the focal length of the optical system is The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are respectively ,in and Meet the following ratios: .

[0031] In this embodiment, the first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the sixth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

[0032] In this embodiment, the total optical length TTL of the optical system and the focal length f of the optical system satisfy the following relationship: TTL / f≤1.5.

[0033] In this embodiment, the image height H of the optical system and the focal length f of the optical system satisfy the relationship: H / f≤1.0.

[0034] In this embodiment, the aperture of the optical system is located behind the third lens, and a filter is provided on the rear side of the eighth lens.

[0035] In this embodiment, the F number of the optical system is ≤1.8.

[0036] In this embodiment, when imaging, light passes through the first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens in sequence from left to right to form an image.

[0037] Example 2: Based on Example 1, in this example, the technical indicators achieved by the optical system are as follows:

[0038] (1) Focal length: 84.0 ≤ EFFL ≤ 85.0 mm;

[0039] (2) Aperture F ≤ 1.8;

[0040] (3) Field of view: 2w ≥ 40°;

[0041] (4) Working band: visible light band.

[0042] To achieve the above design parameters, in this embodiment, the specific design parameters of each lens used in the optical system are shown in Table 1 below:

[0043]

[0044] Table 1

[0045] The optical system of this embodiment achieves a fast focus function while meeting the imaging performance requirements of a full-frame large aperture lens by reasonably allocating the optical power, surface shape, center thickness of each lens, and the on-axis distance between each lens.

[0046] Unless otherwise stated, for any of the technical solutions disclosed in the present invention, if a numerical range is disclosed, the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely a numerical range that is representative or has a more obvious technical effect among many feasible numerical values. Due to the large number of numerical values, it is impossible to enumerate them exhaustively. Therefore, the present invention discloses some numerical values to illustrate the technical solutions of the present invention. Moreover, the numerical values listed above should not be construed as limiting the scope of protection of the present invention.

[0047] At the same time, if the above-mentioned invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, using bolts or screws to connect), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by integral molding using a casting process) (except where it is obviously impossible to use an integrated molding process).

[0048] If words such as "first" and "second" are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only for the convenience of description to distinguish between components. Unless otherwise stated, the above words have no special meaning.

[0049] In addition, unless otherwise stated, the terms used in any technical solution disclosed in the present invention to express positional relationships or shapes include states or shapes that are approximate, similar, or close thereto.

[0050] Any component provided by the present invention may be assembled from multiple separate components, or may be a separate component manufactured by an integral molding process.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention. They should all be included in the scope of the technical solution for protection of the present invention.

Claims

1. A fast-focusing, full-frame, large-aperture micro-single lens, characterized by: an optical system including lenses, the optical system comprising a first lens, a cemented lens group, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, which are arranged in sequence from left to right along an incident optical path of light, wherein the cemented lens group includes a second lens and a third lens, the first lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the second lens is a meniscus concave negative lens, whose object side surface is convex and whose image side surface is concave; the third lens is a meniscus convex positive lens, whose object side surface is convex and whose image side surface is concave; the fourth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the fifth lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; the sixth lens is a biconcave negative lens, whose object side surface is concave and whose image side surface is concave; the seventh lens is a biconvex positive lens, whose object side surface is convex and whose image side surface is convex; and the eighth lens is a meniscus concave negative lens, whose object side surface is concave and whose image side surface is convex; The focal length of the optical system is The focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are respectively ,in and Meet the following ratios: 。 2. The fast-focusing, large-aperture, full-frame micro-single lens according to claim 1, characterized in that: The air gap between the first and second lenses is 0.1~0.5mm; the second and third lenses are a cemented lens group, and the air gap is 0mm; the air gap between the third lens and the aperture is 3.5~4.0mm; the air gap between the aperture and the fourth lens is 1.1~1.5mm; the air gap between the fourth and fifth lenses is 3.1~3.5mm; the air gap between the fifth and sixth lenses is 0.0~0.5mm; the air gap between the sixth and seventh lenses is 22.5~23.0mm; and the air gap between the seventh and eighth lenses is 21.5~22.0mm.

3. The fast-focusing, large-aperture, full-frame micro-single lens according to claim 1, characterized in that: The first lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the second lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the third lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fourth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; the fifth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the sixth lens satisfies the relationship: 1.2≤N d ≤1.5, V d ≥50.0; the seventh lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≥50.0; the eighth lens satisfies the relationship: 1.5≤N d ≤1.8, V d ≤50.0; where N d is the refractive index, V d is the Abbe constant.

4. The fast-focusing, large-aperture, full-frame micro-single lens according to claim 1, characterized in that: The total optical length TTL of the optical system and the focal length f of the optical system satisfy: TTL / f≤1.

5.

5. The fast-focusing, large-aperture, full-frame micro single-lens lens according to claim 1, characterized in that: The image height H of the optical system and the focal length f of the optical system satisfy: H / f≤1.

0.

6. The fast-focusing, large-aperture, full-frame micro single-lens lens according to claim 1, characterized in that: The aperture of the optical system is located behind the third lens, and a filter is provided on the rear side of the eighth lens.

7. The fast-focusing, large-aperture, full-frame micro single-lens lens according to claim 1, characterized in that: The F number of the optical system is ≤1.

8.

8. An imaging method for a fast-focus, full-frame, large-aperture micro-single lens according to any one of claims 1 to 7, characterized in that: The light passes through the first lens, the second lens, the third lens, the aperture, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens from left to right to form an image.

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