They are used in microscopes, binoculars, telescopes, cameras, slide projectors, CD players and many other optical instruments.- Objective (optics)
The earliest known examples of compound microscopes, which combine an objective lens near the specimen with an eyepiece to view a real image, appeared in Europe around 1620.- Microscope
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An eyepiece, or ocular lens, is a type of lens that is attached to a variety of optical devices such as telescopes and microscopes.
The objective lens or mirror collects light and brings it to focus creating an image.