» For the device for looking through a camera, see viewfinder. An eyepiece, or ocular lens,'s a type of lens that's attached to a variety of optical devices such as telescopes and microscopes. It's so named because it's usually the lens that's closest to the eye when someone looks through the device. The objective lens or mirror collects light and brings it to focus creating an image. The eyepiece's placed at the focal point of the objective to magnify this image. The amount of magnification de… (More on Eyepiece)