Diopter (disambiguation)
Encyclopedia
In modern usage, diopter
or dioptre is a measure of the refractive power of an optical system.
Diopter may also refer to:
Dioptre
A dioptre, or diopter, is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres . It is thus a unit of reciprocal length. For example, a 3-dioptre lens brings parallel rays of light to focus at metre...
or dioptre is a measure of the refractive power of an optical system.
Diopter may also refer to:
- Any lens system, such as a telescopeOptical telescopeAn optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for making a photograph, or collecting data through electronic image sensors....
- A diopter sightDiopter sightThe diopter is an aperture sight component used to assist the aiming of a guns/devices, usually those intended to launch projectiles, such as firearms, airguns, and crossbows...
- A close-up lensClose-up lensIn photography, a close-up filter, close-up lens or macro filter is a simple secondary lens used to enable macro photography without requiring a specialised primary lens...
used in photography - A theodoliteTheodoliteA theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...
or similar surveyor's angle measuring device - A dioptraDioptraA dioptra is a classical astronomical and surveying instrument, dating from the 3rd century BCE. The dioptra was a sighting tube or, alternatively, a rod with a sight at both ends, attached to a stand...
, an old surveying device - An alidade
- A surgical speculumSpeculum (medical)A speculum is a medical tool for investigating body cavities, with a form dependent on the body cavity for which it is designed. In old texts, the speculum may also be referred to as a diopter or dioptra...
- An instrument for drawing the skull by projections