1. f-NUMBER
The f-number indicates the brightness of the image formed by the lens, controlled by the iris. A smaller f-number means a brighter image.
2. f-STOP
A term used to indicate the speed of a lens. The smaller the f-number, the greater is the amount of light passing through the lens
3. FEEDBACK
The process of returning a control signal from one part of the system to an earlier stage in a mechanical or electrical system. A feedback is degenerative
( also known as negative or inverse ) when the feedback signal is out of phase at the point where it is injected to the main signal. It tends to decrease
the amplitude of the main signal. It is regenerative ( also known as positive) when the feedback signal is in phase with the main signal at the point of
injection. It tends to increase the amplitude of the main signal.
4. FIBRA ÓPTICA
Fibras de vidro flexível usada para transmitir dados ou imagem em forma de luz.
5. FIELD
One of the two equal parts into which a television frame is divided in an interlaced system of scanning. It consists of 262 1/2 horizontal scanning lines.
6. FIELD FREQUENCY
The number of fields transmitted per second in a television system. The N.T.S.C. standard is 60 fields per second.
7. FIELD OF VIEW
The horizontal or vertical scene size at a given distance from the camera to the subject.
8. FILTERS
1. N.D. ( neutral density ) is a filter that filters the entire wavelength.
2. U.V. ( ultraviolet ) is a filter that absorbs short wavelength of ultraviolet rays, prevents natural light from giving a bluish green cast to shaded areas.
It is also called skylight filter.
3. I.R. ( infrared ) is a filter that blocks infrared light which causes blooming and affects resolution.
4. C.C. ( color correction ) TV cameras are designed for standard illumination approximately 3000K to 3200K. As an example sunlight is approximately
5600K and fluorescent light is 4300K. C.C. filters correct for these color temperatures and change them back to 3000K.
5. Polarizer is a filter that intercepts reflected light from water or glass.
9. FILTRO PASSA FAIXA
Um filtro que passará só uma faixa específica de freqüências.
10. FLANGEBACK
The distance from the lens flange surface to the image plane.
11. FOCAL LENGTH
The distance from the center of the lens to a plane at which point a sharp image of an object viewed at an infinite distance from the camera is produced.
The focal length determines the size of the image and the angle of the field of view seen by the camera through the lens. That is the distance
from the center of the lens to the pickup device.
12. FOOTCANDLE
It is the light intensity ( illumination ) of a surface one foot distant from a source of one candela. It is equal to one lumen per square foot. ( 1 FC =1 Im ft2 ). The footcandle is the unit used to measure incident light.
13. FOOTLAMBERT
The unit used to measure the emitted or reflected light from a surface. For a perfect reflecting and diffusing surface, the number of footlamberts will be
equal to the number of footcandles.
14. FRAME
Em comunicação de dados, frame é um grupo de bits que forma um bloco adequado à transmissão como unidade. Cada frame segue a mesma organização básica, como a sincronização de caracteres, endereço e rotinas de verificação. O frame relay é um conjunto de especificações que determina a necessidade de enviar cada frame a um intervalo regular.
15. FREQUENCY RESPONSE
The range or band of frequencies to which an electronic equipment offers essentially the same characteristics.
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