| fisheye lens |
a wide-angle camera lens that covers a full 180 degrees, producing images characterized by peripheral distortion and dramatically foreshortened perspective. |
| f-number |
the relative aperture of a camera lens, representing the light it will transmit, which is obtained by dividing the focal length of the lens by the diameter of the aperture. |
| focal length |
the distance between the optical center of a lens or curved mirror and the far distant point where light rays converge upon an object. |
| Fresnel lens |
a thin and relatively flat optical lens made of many stepped concentric rings, and having the properties of a thicker, more concave lens. |
| f-stop |
for a camera lens, an aperture setting corresponding to an f-number. [1/2 definitions] |
| gobo |
a dark screen used to reduce the amount of light that reaches a motion picture or television camera lens. [1/2 definitions] |
| lensless |
combined form of lens. |
| loupe |
a small, high-powered magnifying lens used by jewelers, that is held or worn close to the eye. |
| magnify |
to cause to appear larger, as through the use of a lens. [1/4 definitions] |
| magnifying glass |
a lens that enlarges the image of objects seen through it. |
| microscope |
an instrument using a lens or lenses to magnify extremely small objects, esp. those not visible to the unaided eye. |
| objective |
in optical instruments such as telescopes and microscopes, the lens closest to the object being observed. [1/7 definitions] |
| opacity |
something that is opaque, such as a spot on the cornea or lens of an eye. [1/4 definitions] |
| optic |
a part, esp. a lens, of a device that bends light, as for correcting vision or magnifying. [1/3 definitions] |
| peep show |
an exhibition of pictures or objects, as in a box, to be viewed through a small opening, sometimes with a magnifying lens. [1/2 definitions] |
| plano-concave |
having one flat and one concave side, as a lens. |
| plano-convex |
having one flat and one convex side, as a lens. |
| presbyopia |
inability to focus on nearby objects due to age-related hardening of the lens of the eye. |
| reflex camera |
a camera fitted with a mirror behind the lens which reflects the image onto a ground glass plate to achieve an exact focus. |
| resolving power |
a measure of the smallest distance at which a photographic plate or lens can define the fine detail of an image. [1/2 definitions] |
| shutter |
a device that opens and closes the lens of a camera. [1/4 definitions] |