To figure the total magnification of an image that you are viewing through the microscope To figure the total magnification of an image that you are viewing through the microscope is really quite simple. To get the total magnification take the power of the objective (4X, 10X, 40x) and multiply by the power of the eyepiece, usually 10X is really quite simple. To get the total magnification take the power of the objective (4X, 10X, 40x) and multiply by the power