focal length

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focal length

n. Abbr. f
The distance of a lens or mirror to its focal point. Also called focal distance, focus.

focal length


focal distance

(General Physics) the distance from the focal point of a lens or mirror to the reflecting surface of the mirror or the centre point of the lens

fo′cal length`

the distance from a focal point of a lens or mirror to the corresponding principal plane.
Also called fo′cal dis`tance.

fo·cal length

The distance from the surface of a lens or mirror to the point where the light rays converge to form an image (the point of focus).
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.focal length - the distance from a lens to its focusfocal length - the distance from a lens to its focus
distance - the property created by the space between two objects or points
ohnisková vzdálenost
distância focal
References in periodicals archive ?
Of course, the pro-model standard zoom, now typically a 24-70mm, is a far better lens than its previous incarnations, with outstanding optical quality across its focal length range, including the 50mm setting.
The lenses are available in 21 models with focal lengths of 4mm, 6mm or 12mm and feature working distances that are very short or zero.
Because I had no other choice of focal length, I researched and tried to learn everything I could about focal length.
The time-honored solution to this ergonomie difficulty is to combine an eyepiece of moderately long focal length (and thus comfortable eye relief and an eye lens of reasonable diameter) with a Barlow lens or other image amplifier that doubles or triples the magnification.
The new CJ20ex7.8B includes a built-in 2x extender, which even when shooting at the 312mm telephoto-end focal length, delivers superior optical performance to support use with 4K broadcast cameras.
One might now ask--if Digges had had access to optics similar in size and focal length to those that I used, would he have produced a viable terrestrial telescope?
Rhodri Clark.: How they work:Any camera lens has a focal length, the distance from the film to the main focal point of the lens.
The simplest way to increase the field of view is to use a low-power eyepiece, but ultimately a scope's field of view is limited by its focal length and by the diameter of the focuser tube.
Alternatively, lenslets for such an array could be made with a much lower numerical aperture (which automatically reduces their optical aberrations) while still having a focal length much smaller than would be possible with macroscopic lenses.
However, since there is only one focal length, there are only three lens parameters, F, [Alpha] and [Beta].