Virtual images from converging and diverging lenses

When rays of light are brought to a focus a real image forms. A real image can be projected onto a screen. Virtual images occur at points where rays appear to (but do not actually) originate from. They cannot form on a screen. The size and position of a virtual image is found by drawing virtual rays to find where rays appear to originate from. Upright virtual images are produced by diverging lenses, and objects within a focal length of a converging lens. Converging lenses fix long sight by shortening the focus. Diverging lenses fix short sight by lengthening the focus.