When you change from low power to high power on a microscope, the high-power objective lens moves directly over the specimen, and the low-power objective lens rotates away from the specimen. This change alters the magnification of a specimen, the light intensity, area of the field of view, depth of field, working distance and resolution. The image should remain in focus if the lenses are of high quality.

The field of view is largest on the lowest power objective. When you switch to a higher power, the field of view closes in towards the center. You will see more of an object on low power. Therefore, it is best to find an object on low power, center it, and then switch to the next higher power and repeat.