What is a lens? What are the different types of lenses?

Lens [jìng tóu].

The lens has two fingers in film and television, one refers to the optical components used by the movie camera and projector to generate the image, and the other refers to a continuous picture shot from the start to the shutdown, or the clip between two editing points, which is also called a lens.

One finger and two fingers are two completely different concepts, in order to distinguish the difference between the two, one finger is often referred to as an optical lens, and the other is referred to as a lens picture. According to the origin of the lens, it is mainly classified as Japanese lenses and German lenses. Japanese lenses are mainly reproduced in color.

It's better, and the layering of German lenses is stronger. Chinese lenses in the market are also gradually occupying a certain market, mainly because they are relatively cheap.

A lens that is relative to a prime lens with an immutable focal length. Most zoom lenses (DSLRs) can change the focal length by twisting the zoom ring on the lens (the scene also changes) You see those lenses that will elongate and shorten when twisted, which are zoom lenses, which are more convenient to use. However, compared with the prime lens, the image quality and aperture coefficient in the same range are inferior to those of the prime head.

The main function of the lens is to collect the reflected light of the illuminated object and focus it on the CCD, the image projected onto the CCD is inverted, and the camera circuit has the function of inverting it, and its imaging principle is the same as that of the human eye.

The camera has that meaning in film and television.

One is a movie camera, a projector used to generate images.

optical components.

The second is a continuous picture taken from boot to shutdown.

1. According to the focal length, there are fixed focal length type, telescopic type, automatic aperture or manual aperture and other types.

2. According to the size of the focal length number, there are standard lenses, wide-angle lenses, mountains, telescopic lenses and other types.

3. According to the aperture, there are fixed iris type, manual iris type, automatic iris type (autoiris) and other types.

4. According to the lens telescopic adjustment method, there are electric telescopic lenses, manual telescopic lenses and other types.

A telephoto lens means a photographic lens that is longer than the focal length of a standard lens. Long focal length lenses are divided into two categories: ordinary telephoto lenses and super telephoto lenses. The focal length of a normal telephoto lens is close to that of a standard lens, while the focal length of a super-telephoto lens is much larger than that of a standard lens.

Take the 135 camera as an example, the lens focal length from 85 mm to 300 mm is an ordinary telephoto lens, and the 300 mm or more is a super telephoto lens.

Telephoto lenses are also known as telephoto lenses and telephoto lenses. Focal lengths range from 135-800mm, and some even longer.

In the process of photographing distant objects, it is often found that it is impossible to get closer to the subject. This requires the use of a telephoto lens, which can well represent the details of distant objects and capture some subjects that are not easily accessible to us.

The focal length of the focal length of the focal length is small, and the image on the negative is large. As a result, larger images can be captured at the same distance than standard lenses. Ideal for shooting distant subjects.

Because its depth-of-field range is smaller than that of a standard lens, it can blur the background more effectively to highlight the subject in focus, and the subject is generally far away from the camera, so there is less distortion in the perspective of the portrait, and the portrait is more vivid, so people often refer to the telephoto lens as a portrait lens.

However, the telephoto lens has a longer barrel, heavy weight, ** is relatively expensive, and its depth of field is relatively small, which is difficult to align with the focus in actual use, so it is often used in professional photography.

Types: Long focal length lenses can be divided into three types: general telephoto lens, inverted telephoto lens and reflective telephoto lens according to the different light group structures.

Features: Shooting with a long focal length lens has the following characteristics:

Small angle of view: Therefore, the spatial range of the scene is also small, and the image captured at the same shooting distance is larger than that of a standard lens, which is suitable for shooting the details of distant scenes and subjects that are not easy to approach.

Short depth of field: As a result, subjects in cluttered environments can be highlighted. However, this makes it difficult to focus accurately, and if the focus is slightly imprecise when shooting, the subject will be blurred.

Poor perspective: This lens has the characteristics of significantly compressing the depth distance of space and exaggerating the background. When used with long focal length lenses, they are generally used to shoot distant scenes.

Due to the absorption of air and the influence of diffuse scattered light, it is not easy to achieve very accurate focusing due to the small contrast of the captured images and the severe extinction of dust particles. Shooting with a super-telephoto lens of 300mm or more makes it difficult to concentrate various colors of light in one point, resulting in a sub-spectrum problem.

<>1) Basic meaning: A lens on a camera or projector. It is used to create an image on film or screen.

2) (Name) A picture of a photograph.

3) A series of images taken from the beginning of the camera to the time it stops.

How to buy lenses:

The first lens should choose a wide range of focal length coverage, including from wide angle to telephoto, which is usually called a zoom lens, more typical like -105, many cameras leave the factory, will be equipped with a set of lenses, usually this is a zoom lens, novices use this lens as a basic lens for early shooting learning.

Regarding the meaning of the lens, the computer jargon is explained.

A lens is a structure that concentrates light so that the film can obtain a clear image. Early lenses consisted of monolithic convex lenses. Because of the poor clarity, chromatic aberration will be generated, and it is gradually improved into a compound lens, that is, the combination of multiple concave and convex lenses to correct various aberrations or chromatic aberrations, and through the lens coating (coating) treatment, increase the amount of light, reduce flare, so that the quality of the image is greatly improved.

Generally speaking, the lenses used in photography are focusing lenses, and according to the optical principle, after the light from a distance passes through the lens with a focusing effect, it will focus on one point, which is the focus. The distance from the focal point to the center point of the lens is called the focal length. On a camera, the center point of the lens is usually at the aperture, and the focus is on the focal plane (i.e., the film face).

Therefore, the focal length of the camera is the distance from the aperture to the film when the lens is in focus at infinity. Types of lenses (classified according to application) Wide-angle lens: the angle of view is more than 90 degrees, the observation range is large, and the near image is distorted.

Standard lens: The angle of view is about 30 degrees, and it has a wide range of use. Telephoto lens:

The angle of view is less than 20 degrees, and the focal length can reach tens of millimeters or hundreds of millimeters. Zoom lens: The focal length of the lens is continuously variable, and the focal length can be changed from wide angle to telephoto, and the longer the focal length, the larger the image.

Pinhole lenses: used for covert observation and are often installed in places such as ceilings or walls.