In the table below, indicate what happens to each parameter (circle "increases" or "decreases") as
you rotate through the objective lenses starting with scanning and ending with oil immersion)
Quality modern microscopes have parfocal objective lenses (having focal planes in the same
position). For the user, this means that as the objective lenses are changed, the specimen remains in
focus. In reality, even the most expensive microscopes do not have perfectly parfocal lenses, so a
slight adjustment in the fine focus is normally required as the objectives are changed. To rotate the
objective lenses, turn the nosepiece. Do not grasp and turn the lens as this causes them to loosen
and become less parfocal, more susceptible to vibration, and likely to fall off and become damaged.
Should the stage be lowered to prevent the objective lens from hitting the slide when you change
to the next higher-powered objective? Why or why not?