A parfocal lens is a zoom lens that holds its focus throughout its entire zoom range. A varifocal lens, on the other hand, is a zoom lens that requires the lens to be refocused if the focal length is changed.
A lens used in both contacts and eyeglasses works by changing the direction of light and bending it so that it focuses on the retina of the eye. For nearsighted people, a lens "diverges the light rays, which reduces the eye's focusing power," according to Gary Heiting, ...
A hand lens is used to magnify items. Hand lenses are used in scientific research, police work and everyday life. Hand lenses are magnifying glasses small enough to be held in a hand and easy to manipulate.
The two main functions of the lens of the eye are to focus light onto the retina and to help the eye focus on objects at various distances. The lens of the eye is a rubbery, jellylike structure. It is located behind the cornea and is held in place by tendons that are at...
A cultural lens is another term for viewing things from the perspective of a foreign culture. In order to apply a cultural lens on a situation, soft skills like empathy and understanding are needed.
Parfocal microscopes maintain focus throughout real-time magnification changes. These microscopes also remain focused when the user rotates objectives. This capability is a function of the lens and is a particularly popular feature on field microscopes. Parfocal lenses ...
A condenser lens is the part of a compound microscope responsible for focusing light on the slide. This lens is included on almost all microscopes manufactured since the 19th century and is usually found on the bottom of a microscope below the stage and above the electr...