What is the purpose of a Flash-Gun and a diffuser?

Answer 1

A flashgun is simply a shoe mount flash, that can be triggered either by the hot shoe of the camera itself, a sync cable, or wireless trigger and is most commonly used to provide better fill ratio lighting than is possible with the built-in variety flash found on most cameras, and even in addition to. A diffuser is any device [or object] that diffuses the harsh light from a strobe by way of bouncing it off of or shooting it through a diffuse material such as a translucent fabric or plastic, and a wall or ceiling. Light diffusion can also be achieved by the use of a reflector or umbrella with reflective inner lining. You could even use a cereal box lined with aluminum foil to reflect or boune diffuse light from the flash back onto the subject. This is achieved by spreading out the pattern of light emitted by the strobe light, which is formed into a linear pattern by the fresnel lens element of the speedlight, breaking that pattern effectively softens it.

Answer 2

Flashgun Diffuser

Answer 3

An off-camera flash (aka flash gun in ancient parlance) allows you to use bounce flash, either off the ceiling or a wall (as long as they are white) or a reflective umbrella.

A diffuser is used when there is no possibility of using bounce flash. It is also handy for use with a digicam which is limited to its built-in flash.

Answer 4

Photography is one of my big interests, as well. Flashguns are used to spotlight a subject; diffusers spread and soften the flashgun's output. Probably the best way to maximally diffuse the flashgun is to fire it directly away from the subject, into the underside of a white umbrella; the diffused light will fill its portion of subject illumination without glare, provided that the umbrella is set at the proper distance from the flashgun.