Things to know about the lens

maxime220 — Thu, 02 Sep 2021 07:20:12 +0000

Getting used to using the equipment, the owner often does not wonder how this or that gadget is organized, which helps him in everyday activities. Quite often, it should be taken into account that familiarity with a device of a technique occurs in unpleasant circumstances, for example, during a breakdown. We will understand how to choose and use the camera lens correctly, while taking care of it competently, in order to avoid unpleasant situations related to a failure.

How the lens works

Modern camera lenses do not differ much from their predecessors. The principle of operation and design has not changed for decades. Light particles fall on the matrix and pass through it optical system. The basis of this optical system is the lens. It also includes a viewfinder and a focus sensor. The task of the optical system is to collect the rays of light on the same plane.Here the lens plays an essential role.

Theoretical basis

The principle of the photo lens is based on the laws of optics, that is, the refraction of a light beam as it crosses the boundaries of a medium of different densities. You can see this phenomenon everywhere. For example, in a cup, when mixing sugar in water. Spoon, immersed in tea, looks cracked, deformed just at the border of fluid and air. Light in liquids travels more slowly than in gases, hence the barely perceptible distortion I can observe with my own eyes.

This effect is even more pronounced when the light passes. at the boundary of the air and the lens. The more the lens is twisted, the stronger the effect. As a result of such refraction, an image is projected using a non-geometrically correct, but undistorted matrix.

The main elements of the lens

The camera lens of the camera is quite complicated. It consists of several basic elements

a system of DZO lenses and spherical mirrors made of a specialized material;
metal frame;
aperture.

On the front of the camera is an optic that collects light rays - collecting lens. Inside the camera are optical lenses and mirrors that refract the received rays to form a subsequent image. The optical system of the camera can have a different number of lenses. Depending on the needs, the lenses can be adjacent or have an air gap.

Lens mount - It is not only responsible for the strength of the entire structure, it also serves as a fixation for the optics. Since the arrangement of the lenses requires extreme precision, it is imperative that each lens installed is located at a designated distance, does not move, as this could affect the quality of the shot. Therefore, the frame is often made of durable metal alloys.

The frame has a complex apparatus. Its main part is responsible for the external protection against physical and meteorological effects, usually the optical lenses and the diaphragm are located there. The inner part of the frame (it is also called transitional) is used to move parts along the axis, as well as to establish a solid connection with the body (body, casing) of the chamber. The inner frame is equipped with several ring parts. When one of these rings rotates, the part in which the outer unit is attached moves.

The frame allows you to make automatic or manual adjustments to the iris settings. Aperture is an adjustable hole that controls the amount of light rays entering the interior. It consists of moving metal petals that, taking a different position, regulate the level of rays falling on the matrix. The petals are mobile both around the circle of the optical lens and beyond. This detail is necessary to work with the depth of field when transferring space to the frame. The smaller the aperture, the sharper the image on the frame.

Focusing mechanism and image stabilization

When shooting, another part of the lens plays an important role. With the help of the focus ring the manual focusing is done. When the ring is turned, it focuses on the front or back. The focus ring allows you to work with a variable focal length (the better known name is "zoom", "zoom in on the image", etc.) in manual or automatic mode, of course, if the latter is supported by the model.

Modern camera manufacturers use ultrasonic focusing controls (USM), which are directly integrated into the lenses. With this device, an extremely fast and smooth focusing is provided. Also known as lens with screwdriver. The disadvantage of this system is the slower and noisy work. The screwdriver of the camera is a motor through which occurs the rotation of individual parts, as a result of which the focus takes place. It is located outside the housing, on a metal ring for mounting the camera.

In addition to the autofocus in the lens can be present and stabilization mechanismcompensate for inertia during a long exposure. This allows you to get sharp photos without using a tripod. Varifocal lenses are equipped with a zoom ring, which allows you to change the focusing distance. With these rings, you can greatly enlarge or reduce the object inside the frame.

Types of lenses and their application

For an SLR camera, there are different types of lenses.If the camera is equipped with a fixed lens, the frame will be integrated into the design of the camera. But the most popular models with removable lenses. Different filters can be attached to the lens itself, depending on the methods and location of the shooting. The size of the lenses can also vary considerably.

Whale

Whale lenses are generally preferred by beginners. This is an optic that comes complete with housing. The viewing angles of whale optics are almost identical to those of humans, without taking into account the peripheral vision. This fact makes whale optics very popular, such devices are easy and convenient to use in everyday shooting, to perform simple shots. Sometimes a whale is called a standard or full lens. This is a universal thing for a wide range of applications. The whale lens is distinguished by its low price, as well as its ability to take pictures in almost any format: from a moving object to a portrait or a micro-shot.The quality of the final image varies from low to quite high.

Wide angle

The types of lenses for SLR cameras include a wide angle format. These are lenses that offer a wide range of visibility (from 60 degrees). With the help of such optics, it is very convenient.Shoot a group of people and take pictures in tight spaces. The background at the same time remains slightly blurred. The focal length can reach 28 mm. These lenses cost a lot of money, but in most cases their purchase is justified. Used for weddings and indoor shooting, as well as landscapes.

Fish eye

This is an optic with a defective distortion. The angle of view of this lens can reach 180 degrees. The focusing distance is between 4.5 and 15 mm.

Sometimes this lens is also called "fish". With the help of such lenses, it is convenient to make circular and diagonal photo. Using the "fisheye", often taken photos of the city, as well as photos of extreme sports.

Macro lens

As the name suggests, this is a lens designed to photofilm small objects. As a rule, such a lens allows you to take close-up shots. The focusing distance is between 50 and 180 mm. The maximum aperture value is f / 2/8. A characteristic of this lens is the ability to focus on small objects, as well as the high sharpness of the image and good color reproduction. Most often used in nature photography (insects, flowers, etc.).

Long Focus

Lens with a long focusing distance of 70 to 300 mm. The visibility varies from 39 degrees. These lenses can be of two types: telephoto and telephoto. With regard to the blurring of borders, these two concepts are eventually confused and become identical. Used to photograph objects and events in motion: sports competitions, moments of the natural world.

Portrait optics

Lens with a focusing distance that remains unchanged during operation. Best suited for portraits. Has high light levels. The portrait lens allows you to mask small skin defects.

You can choose a camera lens according to several criteria.

Focal length. One of the most important parameters when choosing a lens. Unfortunately, it is quite difficult to recommend specific parameters, since only the photographer himself can know the minimum focusing distance. As a rule, the most effective lenses have a short focusing distance. To measure the focal length, it is necessary to measure the distance between the focal plane and the subject.

Aperture. The most important criterion for those who plan to shoot in low visibility and poor lighting conditions. Lenses with high light levels are generally of very high quality. If possible, it would be best to purchase lenses with the highest brightness value. It is important to remember that a constant aperture value for the lens is better, because the brightness values change with the focusing distance.

Image stabilization. This setting has a professional lens model. Cameras with long focal length photography need stabilization the most.The best image stabilizer so far in almost all weather conditions was and remains the most ordinary tripod. However, if the model has a built-in stabilization system, you should probably use it.

Mount. Lens mounting is an open and debatable issue among professionals. To date, no universal type of accessory has been developed that the major players in the photographic equipment market would adhere to. Each manufacturer produces lenses with a unique mount, designed only for their own equipment. With the exception of several lenses that claim to be universal, the technical problem of attaching the lens to the camera body is not worth it. Buying a certain body, the future owner already knows what company he will have for a lens.

How to make a change of lens

The first and very important point to observe is the cleanliness of the room in which the replacement takes place. It is desirable that the room has no air flow. The device is placed on the screen with a soft cloth to avoid scratches. Next, you need to prepare the lens, which should be installed. It is desirable that it was within reach all this time. With the finger of the left hand press the unlock button, after which you can unscrew and remove the lens. Unscrew the lens counterclockwise. It should be put aside.

Then we take a new lens in our hands and attach it in red or white dots (depending on the manufacturer). Once the lens has entered the corresponding grooves, it should be carefully screwed clockwise. When the wire is completely twisted, a distinctive click will sound, indicating that the process is complete.

When replacing the lens, various problems may arise. If the lens is stuck, then a few simple steps should be taken:

check the instrument display for lens errors;
recall if the camera has recently suffered any physical damage;
ask for clarification in the user manual.

If the main diagnosis did not help, it is necessary to hit his palm to the side. Light blows to the body sometimes help to resume the work of the stuck lens. Among the options, you can try to clean the tube and connect the camera by the cord to charge it. Sometimes the problem can be hidden by the lack of battery charge.

Still not extend the lens? It can be done by hand. To do this, gently rotate the lens with your fingers, not in automatic mode. Sometimes you can slightly push or try to pull the lens. You can also put the camera with a lens and bang it on the palm of your hand, bent into a handle. If there is a click, it means that the lenses have returned to their original position.Sometimes you can try forced autofocus. In some cases, it is possible to correct the images with such an error.

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