Tell me something about photography. For example, various camera structures (picture). Thank you! ! !

The basic components of a camera

The lens focuses the scene into an inverted image on the film. In order to achieve clear images of objects at different locations, in addition to correcting aberrations in the lens itself, the object distance and image distance should also maintain a yoke relationship. For this reason, the lens should be able to move forward and backward to adjust the focus, so better cameras should generally have a focus adjustment mechanism.

1. Lens

The lens focuses the scene into an inverted image on the film. In order to achieve clear images of objects at different positions, in addition to correcting aberrations in the lens itself, the object distance and image distance should also maintain a yoke relationship. For this reason, the lens should be able to move forward and backward to adjust the focus, so better cameras should generally have a focus adjustment mechanism.

2. Viewfinder

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

3. Mechanisms for controlling exposure - shutter and aperture

In order to adapt to different light and dark subjects and obtain the correct light sensitivity on the film, the length of the exposure time must be controlled and the intensity of light entering the lens. Therefore, the camera must set the shutter to control the length of the exposure time, and set the aperture to control the amount of light by adjusting the aperture size.

4. Film feeding and counting mechanism

In order to prepare for the second shooting, the exposed film needs to be pulled away, and the exposed film needs to be pulled over, so modern cameras need to have a film feeding mechanism mechanism. In order to indicate the number of shots of the film, a counting mechanism is needed.

5. Body

It is not only the camera obscura, but also a combination of the various components of the camera. A block diagram can be used to represent the most basic components of a camera.

In fact, as far as the basic function of a camera is concerned, there is not much difference in its basic principles whether it is the early "daguerreotype camera" or today's highly electronic, automated, and computerized camera.

Classification of cameras

Cameras can generally be classified according to their technical characteristics such as frame size, viewfinding method, shutter mode, and metering method. They can also be classified according to their appearance and structure. to classify. The specific classification is as follows:

(1) According to the film and frame size used by the camera

it can be divided into 35mm cameras (often called 135 cameras), 120 cameras, 110 cameras, and 126 cameras , medium format cameras and large format cameras, etc. The 135 camera uses 35mm film, and the standard frame it shoots is 24mm X 36mm. Generally, each film can take 36 or 24 pictures.

(2) According to the appearance and structure of the camera, it can be divided into head-up viewfinder cameras and single-lens reflex cameras. There are also twin-lens reflex cameras, folding cameras, transfer cameras, landline phones, and more.

(3) According to the shutter form of the camera,

it can be divided into lens shutter camera (also called center shutter camera), focal plane shutter camera, program shutter camera, etc.

(4) According to the functions and technical characteristics of the camera,

it can be divided into automatic focusing cameras, electric metering manual exposure cameras, electric metering automatic exposure cameras, etc. In addition, there are shutter-priority, aperture-priority, program-controlled, dual-priority, electric winding (automatic winding and rewinding) cameras, autofocus (AF) cameras, date-back cameras, built-in flash cameras, etc.

Sometimes the camera can be divided according to its purpose, such as one-step imaging camera, stereo camera; sometimes it can also be divided into zoom or bifocal camera according to the characteristics of the lens. In fact, a modern camera often has many characteristics and should therefore be defined in a comprehensive way.

Viewfinder functions and classifications

When people take photos, they need to find a view in order to select the range of the subject. The viewing device on the camera used to display the imaging range equivalent to the photographic film is called a viewfinder. It is a simple optical system, used to determine the shooting range and layout of the picture.

Modern camera viewfinders often also include:

(1) Focusing and ranging systems.

(2) It can display necessary information for photography, such as shutter speed; aperture and exposure signals indicating whether it is appropriate; flash charging signal, etc.

(3) Configure a metering system that can control exposure.

When visually observing a good camera viewfinder, its field of view and image should be clear and bright; the image should be an erect image of appropriate size; there should be no spatial parallax and time parallax; no light Halos, ghosts and phantoms; in particular, distortion should be eliminated; focus and distance measurement should be correctly adjusted; the depth of field range of the film should be judged; and the necessary information for photography should be provided to the observer.

There are many structural types of viewfinders, and the classification methods are also different. According to whether the viewing optical axis coincides with the photographic optical axis, it can be divided into a coaxial viewfinder and a side-axis viewfinder; according to the virtual reality of the image, it can be divided into a real image viewfinder and a virtual image viewfinder; according to the actual image The structure can be divided into frame viewfinder, Newton viewfinder, inverse Galilean viewfinder, Kepler viewfinder, Albada viewfinder, etc.

Most of the viewfinders of 35mm cameras currently on the market adopt range-axis head-up type and single-lens reflex viewfinder coaxial type.