What is a Lens?

Lens is a kind of optical clarity kit made by one or more optical glasses spherical. It is applied for focalizing or scattering light from targets, so as to form real image or virtual image. There are many kinds of lenses. According to focus, lens can be short focus, middle focus, long focus or adjustable focus; according to viewing scope, lens can be wide angle, standard or telephoto; according to structure, lens can be fixed aperture monofocus, manual aperture monofocus, auto aperture monofocus, manual zoom, auto aperture motorized zoom lens zoom or motorized triple zoom (aperture, focal length and focus are adjustable).