Nosepiece and objectives

Most microscopes have a revolving nosepiece which will hold up to four or five objectives. The nosepiece should be rotated using the knurled ring at the top of the nosepiece, not by applying pressure on the objectives themselves! The objectives usually carry information that tells you more about the magnification and numerical aperture (NA) of the objective. Most student microscopes have fairly simple objectives, but are none the less adequate to be able to resolve very small objects.