focal ratio


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focal ratio

n
(Photography) photog another name for f-number
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.focal ratio - the ratio of the focal length to the diameter of a (camera) lens system
ratio - the relative magnitudes of two quantities (usually expressed as a quotient)
References in periodicals archive ?
Increasing the focal ratio ("stopping down the lens") decreases the opening through which the light enters the camera and restricts the amount of light that's focused onto the image sensor.
The optical bench measures focal ratio degradation (FRD) in specific optical fiber samples to determine if the fibers are appropriate for astronomy applications.
Another consideration is the focal ratio or 'speed' of the lens: f/1.
The fibre uses a large core-to-clad ratio to reduce stress transfer to its core, maintaining laser beam quality and improving focal ratio degradation in lasers used for cutting, welding, drilling, soldering and marking.
Many spectroscopic applications require high performance optical fibres that transmit light over a broad spectrum and demonstrate minimal focal ratio degradation.
The parameters are element spacing (d), focal ratio (g), lens width (G), and scan angle ([alpha]) (Figure 1).
The focal ratio is considered critical because it holds expenses down by reducing the height of the building needed to house the telescope.
A two-stage concentrator works best if you have a moderately long focal ratio design, that is, where the focal length is substantially greater than the diameter of the aperture of the primary of the focusing mirror," said Joe O'Gallagher, a senior research associate and senior lecturer in the Physics Department at the University of Chicago and a colleague of Winston's since 1976.
Many spectroscopic applications require high performance optical fibers that transmit light over a broad spectrum and demonstrate minimal focal ratio degradation.
Modest vignetting of the field using the T-thread adapter was easily controlled with flat-field calibration at the relatively slow focal ratio of the instrument.