Why do professional photography or filming use film instead of digital?

The origin of film is recorded on film, not only its clarity is higher than that of digital; Its principle also lies in that the film records the image through the chemical change of silver bromide, while the digital image is transmitted through the optical lens, converted into digital data by the digital converter and stored on the memory card, and the intermediate conversion is from physical parameters to digital data. You can imagine which is clearer.

Please see the following discussion:

First, the principle of film formation

Each film (including color film) consists of two basic components: a single or multi-layer latex layer and a film base, which is the support of the latex layer. Emulsion is made of photosensitive particles suspended in gelatin medium. The gelatin on the film is similar to that used in some foods.

The photosensitive substance suspended in gelatin is silver halide particles. This kind of particle is so fine that it can only be observed under a high-power microscope. In 1 square inch photographic film emulsion, the content of silver halide crystals is about 40 billion!

Silver halide crystal has the characteristic that its structure will change once exposed to light. The mechanism of this chemical change is not important to us, but the final effect of the change is the most important. How did this change come about? When you shoot, the light shines on the emulsion layer of the film through the lens of the camera. When light reaches silver halide crystals, these crystals undergo structural changes and combine with adjacent silver halide crystals that are also irradiated by light.

This lump of silver halide crystals is still extremely small. The more light the latex layer receives, the more crystals will coalesce, and the less light, the less crystal changes and coalescence. Without light falling on the emulsion, there will be no crystal change and coalescence. That is to say, when different intensities of light are irradiated on the film, different numbers of crystals in the microscopic field of the film emulsion layer undergo structural changes and coalesce with each other.

Once the film is exposed, it immediately produces a latent image-an invisible image. The film must be developed to transform the latent image into a visible solid image. When the film is developed, the silver halide crystal whose structure has changed will turn into an aggregate of black metallic silver particles, thus producing a negative image. Those crystals on the film that are not sensitive to light, that is, those that have not undergone structural changes, are washed away by a chemical called fixing agent, making these parts appear light gray or transparent. The result is that the dark (thick) part of the negative image is the exposed part; The bright (thin) part is the part with less exposure; The completely transparent part is the part that is not irradiated by light. This is the basic process of black-and-white film recording images.

Second, the imaging principle of digital camera

The imaging principle of digital camera can be simply summarized as follows: CCD receives the image transmitted by optical lens, converts it into digital signal through A/D converter, and stores it in memory. The optical lens of a digital camera, like a traditional camera, focuses the image on a photosensitive device, that is, a charge-coupled device (CCD). C CD replaces the position of photosensitive film in traditional cameras, and its function is to convert optical signals into electrical signals, which is the same as TV shooting. CCD is a semiconductor device and the core of digital camera. The number of units containing devices determines the imaging quality of digital camera pixels. The more units, the better the imaging quality. Usually, the pixel level represents the grade and technical index of a digital camera. CCD converts the optical signal of the subject into an electrical signal-an electronic image, which is an analog signal. It also needs to be converted into digital signals to create conditions for computer processing, and it will be converted by analog-to-digital converter (A/D). After the digital signal is formed, the microprocessor (MPU) compresses the signal and converts it into a specific image file format for storage. The liquid crystal display (LCD) of the digital camera itself is used to check the quality of the captured image, and it can also be directly transmitted to the computer for image processing, printing, surfing the Internet, etc.