Flash - Samsung NX1000 User Manual

Flash
Light _sone of the most _mportant corroonents Enphotography. It's
no_ east, however to have an enougn amount of light anst_me an_
arj where. Making use of a flash allows you to oot_mJzelight settings
and create a variety of effects.
Flash, also known as strobe or speed light, helps to create adequate
exposure in Iowqight conditions. It is also useful in light-abundant
situations. For example, flash can be used in compensating the
exposure of a subject's shadow or capturing clearly both the subject
and the background in backtit conditions.
Before correction After correction
The model number of a flash refer
maximum amount of light created is reF
as a "guide number." The bigger the guide number, the mo ts
emitted from the flash. The guide number is achieved by multiplying the
distance from the flash to the subject and the aperture value when the
ISO sensitivity is set to 100.
Guide number = Flash to Subject Distance X Aperture value
Aperture value = Guide number / Flash to Subject Distance
Flash to Subject Distance = Guide number / Aperture value
Therefore, if you know the guide number of a flash, you can estimate an
optimum flash to subject distance when setting the flash manually. For
example, if a flash has a guide number of GN 20 and is 4 meters away
from the subject, the optimal aperture value is F5.0.