Why does the camera lens have film?

Why does the camera lens have film? With the development of science and technology, cameras and mobile phones have become the media for people to record their lives, but many photographers still like to take pictures with cameras to record their lives, but many people don't find film on the camera lens, so why is there film on the camera lens?

Why does the camera lens have film? Why does the camera lens have film?

As early as the end of19th century, shortly after the invention of the camera, the scientist Taylor stumbled upon a very strange thing. He took photos with a camera and found that the photos taken with dirty lenses were clearer and more effective. However, he did not conduct in-depth research.

Forty years later, this phenomenon caught the attention of another scientist, Bauer. He did research and took many photos. So, Bauer discovered a secret: adding a film to the lens, although the reflectivity is very poor, it seems that the lens is not very bright, but in fact it greatly increases the transparency. If a film is coated on the lens, the light of a certain color reflected from the upper and lower surfaces of the film may cancel each other out. There is no light of this color in the reflected light, so where is the light of this color hidden? It turns out that they all enter the lens through the film, so the brightness of this color light is enhanced through the lens film.

Since then, when making cameras, people often paint the lens of the camera with purple substances, so that the photos taken are clearer, more layered and more effective. Of course, the processing of this layer of material requires high technology.

Why is the camera lens purple?

Because the lens is coated with a thin film, people's eyes are sensitive to green light, so the function of the thin film is to increase the transmission of green light and reduce its energy loss through the interference principle of light. However, due to the different wavelengths and frequencies of light, this film cannot reduce the energy loss of other light, so the lens looks like purple light and red light. With the continuous progress of technology, according to the shooting requirements, the camera lenses are now painted with other colors.

How to see if the lens coating is damaged?

As we all know, the coating of camera lens is easy to be damaged, so how can we know whether the coating of camera lens is damaged? Recommend two very simple methods.

Method 1: shoot at the sun (or strong light source) with a small aperture (F8 or below) to see if the glare of the lens in the picture is regular. If there is, it may be the wear of the coating.

Method 2: Take off the lens so that the front of the lens is inclined to the light source. At this time, green, purple, orange or red colors will appear on the lens group of the lens, which is coating. See if there is any vacancy, brightness or incompleteness in this color, which is also the wear of the coating.

Classification of camera lenses

There are many types and kinds of lenses. The basic types of lenses are: zoom lens and fixed focus lens.

Zoom lens: It is a kind of camera lens that can change the focal length in a certain range, so as to obtain different field of view, different images and different scene ranges.

Fixed focus lens: refers to a lens with a fixed focal length, a focal segment or a field of view.

According to the focal length, it is divided into wide-angle lens, standard lens and telephoto lens.

Standard lens: divided by the angle of view, the angle of view of the lens ranges from 40 degrees to 55 degrees, all of which are standard lenses.

Wide-angle lens: A lens whose focal length is less than the diagonal length of the negative is called a wide-angle lens.

Telephoto lens: Also called telephoto lens, this kind of lens has a long focal length, which is much larger than the diagonal of the negative film, so it can take a larger perspective.

Fisheye lens: A fisheye lens is a lens with a focal length of 16 mm or less and a viewing angle close to or equal to 180 degrees.

Macro lens: it is a special lens for macro photography, mainly used to shoot very fine objects, such as flowers and insects.

Axis-shifting lens: the camera does not move, but the lens can move up and down, left and right.

What is the camera lens?

The lens of a camera is not only as simple as convex lens or concave lens, but also convex lens and concave lens, which are the combination of convex lens and concave lens. The effect of overall synthesis is a convex lens. The convex lens can converge the real image to the other side of the lens to form the real image, which exposes the film or electronic photosensitive element, but concave mirror can't.

Why are camera lenses so expensive?

As the saying goes, "SLR destroys three generations", if you are a photographer, you must know that a good camera lens is super expensive, ranging from thousands of entry-level lenses to tens of thousands, hundreds of thousands or even hundreds of thousands of slightly more expensive ones. Why are camera lenses so expensive?

1, the raw glass of the lens is very expensive.

Different from ordinary glass processing, precise optical instruments, not only lenses, but also many elements in glass are strictly controlled, which increases the production cost. Grinding glass is expensive, after all, precision grinding machines are expensive.

2, the camera lens coating is expensive

Coating, modern optical instruments all use multilayer coating, the equipment is equally expensive, and the technology is patented. Fluorite is formed by calcium fluoride crystal, and its optical characteristics are low refractive index and low dispersion, which can greatly improve the color difference. However, pure natural fluorite is too small to be used in SLR camera lenses. Therefore, Canon developed and established the artificial crystallization technology of fluorite, and successfully applied it to the lens. However, even artificial fluorite is expensive, so Canon has developed UD lenses, and two UD lenses can be equivalent to about one fluorite lens. Later, the super UD (super ultra-low dispersion) lens was successfully developed. One super UD lens can provide the effect equivalent to about two UD lenses. At first glance, the effect of super UD lens can be comparable to that of fluorite lens.

3. The cost of lens design is very high

The design of the lens can be done not only by drawing a piece of paper. Need to calculate, such as curvature, glass refraction, how to fold, distance, what image is produced, and so on. Even if these calculations are done by computers now, the input of manpower is very large. The structural design cost of a lens is as high as one million yuan. It is impossible to copy and imitate these designs, and people will apply for patents.

4, the output is small

Designing a lens of 10,000 yuan, the sales volume is generally not high. For example, the sales of Pentax and Sony are basically 10,000, and the sales of some cattle brands such as Canon and Nikon are very strong. The rarer the lens, the less it is sold, the lower the ability to share the cost in design, production and circulation, and the higher the price.

5. Driver class

EF lens has many electronic technologies besides optical structure. Such as image stabilizer, annular USM motor, etc. These are technologies developed for image stabilization and fast focusing. Modern lenses mostly adopt modular design, and some can even be directly simulated by computer. This greatly reduces the design and manufacturing costs of the lens.

How to wipe the camera lens?

Once the camera lens is dirty, it will be very troublesome, because if the wiping method is not correct, the lens coating will be damaged. The following is the correct way to wipe the camera lens.

1. Wear antistatic gloves and try to clean in a dust-free environment. First, blow the dust off the lens surface with air.

2. After removing the dust on the surface, first wipe the whole outside of the camera with lens cloth, and then gently wipe every corner with a pointed cleaning cotton swab dipped in a small amount of cleaning liquid. Don't dip too much cleaning liquid in order to avoid excess cleaning liquid flowing into the camera. If the cotton swab is obviously dirty, continue cleaning with a new cotton swab.

3. If we can't clean the dust on the lens surface by blowing balloons, we can also try to clean the lens with a soft brush. Generally speaking, we can take out dust and other dirty things. For stubborn stains, such as fingerprints, we will use suede, lens cleaning cloth or lens paper with lens cleaning liquid to clean them. When scrubbing, be careful not to squeeze the lens surface hard, because the lens surface is covered with a fragile coating, which can be easily wiped off by hard cleaning.

4. Before using the lens pen, be sure to blow off the lens surface to ensure that there are no dust particles. Then press the lens pen vertically and drive it clockwise from the middle of the lens. Pay attention to blow off the lens toner that falls off the lens surface after one time, then observe the effect, and then wipe and blow! Repeat 4-5 times, the lens should be as bright as new! Experts have said that any act of wiping the lens is harmful to the lens coating! Although the lens pen is a relatively safe tool, you should use it carefully.

5. Use lens cleaner to remove stubborn stains (use carefully)

There are many arguments about whether to use lens cleaning liquid to clean the lens. Some inferior cleaning solutions can really damage the lenses. Therefore, we suggest that if the stubborn stains on the lens can be simply cleaned with tools such as suede, then there is no need to use cleaning solution. Use it as a last resort, and be careful not to use too much and not to touch the cleaning solution outside the lens. Because some cleaning solutions are acetone, it is easy to make the edges of black lenses fade and the lenses are seriously deformed. If the lens has oil stains or fingerprints, blowing and brushing are ineffective. Just gently wipe it with a very soft and clean cotton swab (or mirror paper) dipped in a little lens water. It is not recommended to use lens cleaning solution, which will wash off the coating if used frequently. On the other hand, when the cleaning solution is dry, it will inevitably become dirty again.

Again, no matter how careful you are, wiping with lens water will always damage the lens coating. Don't wipe it easily unless you have to.

6. It is recommended that the time for cleaning the lens should not exceed 30 seconds at a time. Long-term wiping will cause unnecessary damage to the lens.

Why does the camera lens have film? The camera is a kind of equipment that everyone likes very much. It is a kind of equipment that uses the principle of optical imaging to form images and records images with negatives. This is an optical instrument used for photography. In modern social life, there are many devices that can record images, all of which have the characteristics of cameras, such as medical imaging equipment and astronomical observation equipment.

After the light reflected by the shot scene is focused by the camera lens and the shutter that controls the exposure, the shot scene forms a latent image on the photosensitive material in the camera box, and forms a permanent image after being developed and fixed. This technology is called photography, which is divided into general photography and professional photography.

Then why does the camera lens have film?

Originally, all of them were drilled into the lens through film, so the light of this color was enhanced through the lens. Since then, when people make cameras, they often paint a purple film on the lens of the camera, which makes the photos clearer, more layered and more effective. Of course, the processing of this film has technical requirements.