Final answer:
The two names always associated with microscopes are the objective lens and the eyepiece, which combine to magnify the specimen being observed. The objective lens provides initial magnification while the eyepiece further increases this magnification, allowing for detailed examination of small objects.
Step-by-step explanation:
The two names always associated with microscopes are the objective lens and the eyepiece, also known as the ocular lens. The objective lens is the primary lens that magnifies the specimen; it has magnification values typically ranging from 5x to 100x. Standard microscope objectives are parfocal, meaning that when you switch between different objectives, the specimen remains in focus. The eyepiece consists of several lenses within a cylindrical barrel, and it further magnifies the image formed by the objective lens. The overall magnification of a microscope is the product of the magnifications of these two lenses (objective and eyepiece).