Fill light is any source of illumination that lightens (fills in) areas of shadow created by other lights. Most often,
fill light is used to lighten the shadows created by the main (key) light.
A type of photography background which is foldable. It can be double-sided with different colors on each side, transparent,
A fluorescent lamp or fluorescent tube is a low pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce
visible light. (Source: http://en.wikipedia.org/wiki/Fluorescent_lamp).
A large number of continuous lights use fluorescent lamps.
Focusable spotlight which can be adjusted via a knob on the back of the light from "spot" for a narrowly focused beam,
to "flood" for a wider beam. This type of focusable lighting instrument is called a Fresnel because it features a Fresnel Lens,
a glass lens with concentric ripples that is visible on the front of the light, casting soft, even illumination across the light's
Electric arc lamp designed to produce extremely intense, incoherent, full-spectrum white light for very short durations.
Flashtubes are made of a length of glass tubing with electrodes at either end and are filled with a gas that, when triggered,
ionizes and conducts a high voltage pulse to produce the light.
Focus control mechanism
Flash triggers are devices that relay a signal from your digital SLR camera to the flash unit, telling it to fire.
(Source: http://www.digital-slr-guide.com/flash-triggers.html#sthash.rgOc4pC9.dpuf ).
There are different methods to trigger a flash: synch cable, infra-red trigger, wireless trigger, slave trigger, etc