What kind of lens is the camera lens?

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. It is an optical instrument for photography, which consists of lens, viewfinder, fuselage and other parts. The most common camera takes images of visible light, but not all cameras need visible light (such as infrared thermal imager), and some even don't need traditional light source (such as scanning tunneling microscope). In modern social life, many devices have the characteristics of cameras, such as radar, medical imaging equipment, astronomical observation equipment and so on. The earliest camera structure was very simple, including only a black box, a lens and photosensitive materials. Modern cameras are complex, including lens, aperture, shutter, ranging, framing, photometry, film transmission, counting, self-timer, focusing, zooming and other systems. It is a complex product integrating optics, precision machinery, electronic technology and chemistry. With the development of photosensitive materials, dry plates coated with silver bromide photosensitive materials appeared in 187 1 year, and films based on nitrocellulose (celluloid) appeared in 1884. 1888 Kodak company of the United States produced a new type of soft and windable photographic film. This is a leap in photosensitive materials. In the same year, Kodak invented the world's first portable square box camera with film.