What does a camera mean?

Camera, English word, British phonetic symbol is [? k？ Sir? ], the American phonetic symbol is [? k？ Sir? ], a noun, means "camera; Camera ".

A camera is a kind of equipment that uses the principle of optical imaging to form an image and records the image with a negative. 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.

2065438+In September 2008, the Harmonized System Committee of the World Customs Organization classified UAVs as "flying cameras".

There are many kinds of cameras, which can be divided into landscape cameras, printing and plate-making cameras, document microfilm cameras, microscopic cameras, underwater cameras, aerial cameras, high-speed cameras and so on.

According to the size of photographic film, it can be divided into 1 10 camera (picture 13× 17mm), 126 camera (picture 28× 28mm) and 135 camera (picture 24×/kloc).

According to the way of framing, it is divided into perspective framing camera, double-lens reflective camera and single-lens reflective camera.

Any classification method cannot include all cameras, and a camera can be divided into several categories. For example, 135 camera forms a complex spectrum according to its different ways of framing, shutter, metering, film transmission, exposure, flashing, focusing and self-timer.

The camera uses the linear propagation characteristics of light and the law of refraction and reflection of light, takes photons as the carrier, and transmits the light information of the shooting scene to the photosensitive material in the form of energy through the photographic lens, and finally becomes a visible image.

The optical imaging system of the camera is designed according to the principle of geometric optics. Through the lens, the scene image is accurately focused on the image plane through the linear propagation, refraction or reflection of light.

Proper exposure should be controlled when taking pictures, that is, the amount of photons reaching the photosensitive material should be controlled properly. Because the range of photons received by silver salt photosensitive materials is limited, too few photons form latent image nuclei, and too many photons form overexposure, so the image cannot be distinguished.

The camera uses the aperture to change the aperture of the lens to control the amount of photons reaching the photosensitive material in a unit time, and at the same time controls the exposure time by changing the opening and closing time of the shutter.