The lenses on a camera focus the light entering the camera and provide a clear, sharp image at the location of the film or CCD device. If you took the lenses off a camera designed for use with lenses, you would not be able to create a usable image.
A converging lens is used in a camera. The oncoming light from the object focused on a film/screen where the image is stored chemically or electronically.
A convex lens converges a beam of light on the focus. A film is placed there. A digital camera uses a photosensitive screen where image is stored in form of pixels. In the film-camera, the light beam is converged on a film which burns via a chemical reaction storing the image.
