Why can film cameras zoom in infinitely, but digital cameras can't?

The magnification of film negatives depends on the formula when developing the negatives.

For example, in some photo studios, traditional fine recipes are used to minimize the graininess of films. For example, some public security departments use this formula in order to see the image data in a few minutes, but the film is grainy.

When the film granularity is different, we will find that some negatives can only be enlarged into ordinary photos. A little bigger, we will find that the image is blurred and the particles are serious. However, for the film negatives made of exquisite formula, as long as the granularity is invisible to the naked eye, we can enlarge them to any magnification.

On the other hand, the size of the negative film is directly proportional to the magnification of the enlarged photo, so the general 120 negative film magnifies the target photo better than 135 negative film.

In short, the enlargement of film negatives is done by light and shadow.

A digital photo is an image composed of pixels, which are like dots, and also like a piece of cloth woven by criss-crossing lines. The more points, the higher the magnification.

Extended data:

Digital camera, English full name: Digital Still Camera (DSC), short name: Digital Camera (DC), short name of digital camera, also known as digital camera. Digital camera is a kind of camera that uses electronic sensors to convert optical images into electronic data.

According to the use, it is divided into: SLR camera, micro camera, card camera, telephoto camera and household camera.

The principle of digital camera recording images on film through silver bromide's chemical changes is different from that of ordinary cameras. The sensor of digital camera is photosensitive charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS).

Before an image is transmitted to a computer, it is usually stored in a digital storage device (usually using flash memory; Floppy disks and rewritable compact discs (CD-RW) are rarely used in digital camera equipment.

A camera, referred to as a camera for short, is a device that uses the principle of optical imaging to form an image and records the image with a negative. Many devices that can record images have the characteristics of cameras. Medical imaging equipment, astronomical observation equipment, etc.

A camera is an optical instrument used for photography. After the light reflected by the shot scene is focused by the camera lens (scene lens) and the shutter for controlling 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. Divided into general photography and professional photography.

viewfinder

In order to determine the scope of the subject and facilitate shooting and composition, the camera should be equipped with a viewfinder. The viewfinder of modern cameras also has the functions of ranging and focusing.

Shutter and aperture

Mechanism for controlling exposure shutter and aperture

Aperture and shutter

In order to adapt to different subjects with different light and dark, and obtain correct exposure on film, it is necessary to control the exposure time and the intensity of light entering the lens. Therefore, the camera must set the shutter to control the exposure time, and set the aperture to control the light quantity by adjusting the aperture size. ?

Film feeding counting mechanism

In order to prepare for the second shooting, the exposed film needs to be pulled out and the unexposed film needs to be pulled aside, so modern cameras need a film conveying mechanism. In order to display the number of films shot, a counting device is needed.

fuselage

It is not only the black box of the camera, but also the combination of various parts of the camera. The most basic components of a camera can be represented by a block diagram.

In fact, as far as the basic functions of the camera are concerned, whether it is an early "silver camera" or a highly electronic, automatic and computerized camera, there is not much difference in its basic principles.

References:

Baidu encyclopedia-camera