**To determine the total magnification of an image viewed through a microscope, multiply the power of the eyepiece or ocular lens by the power of the objective lens.** If the magnification power of the ocular lens is 10x and that of the objective lens is 4x, total magnification is 40x.

Most compound microscopes have a 10x eyepiece and three objectives, 4x, 10x and 40x. Others also have a 100x magnification power. Therefore, the least total magnification of an image is 40x and the highest is 1000x. In order to view a specimen clearly under the microscope, begin with the lowest power objective (4x) to focus on the specimen, then use higher objective lenses (10x to 100x) to get a closer view of the image.