Magnification is defined as a measure of the ability of a lens or other optical device to magnify a certain image. The ability of a lens to measure size of an object and magnifies to a certain level is the known as a magnification of a lens.
The formula to measure the magnification power of a certain lens is the product of the objective and ocular lens magnification. For example, when using the lower power lens the total magnification is: 10X ocular x10X low power objective = 100X).