Magnification produced by a lens gives the relative extent to which the image of an object is enlarged or diminished with respect to the object size for a linear object held normal to the principal axis of a spherical lens. The linear magnification or magnification is represented as the ratio of the image height to the object height.

M = h’/h 

Magnification produced by a lens is represented in terms of distance of the object and the distance of the image. It is given by:

M = v/u.