• Camera, or camera for short, is a device that USES the principle of optical imaging to form an image and record the image with a negative.
• Many devices that record images have the characteristics of a camera.Medical imaging equipment, astronomical observation equipment and so on.
• A camera is an optical instrument used in photography.After the light reflected from the subject is focused by the photographic lens (landscape lens) and the shutter which controls the exposure amount, the subject forms latent image on the photosensitive material in the dark box, and forms permanent image after developing (that is, developing and fixing). This technique is called photography.Divided into general photography and professional photography.
• The lens focuses the scene inverted onto the film.In order to get a clear image of the object at different positions, besides correcting the camera image difference of the lens itself, the conjugate relation between object distance and image distance should be maintained.To do this, the lens should be able to move back and forth for focus, so a better camera should generally have a focus mechanism.
• In order to prepare for a second shot, the exposed film has to be pulled away and the unexposed film has to be pulled in, so modern cameras need a transfer mechanism.To indicate the number of films taken, a counting mechanism is required.
• It is both a camera camera camera, but also a combination of the components.The most basic components of a camera can be represented by a block diagram.

lens should be able to move back and forth for focus

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