films, as they could produceimages with faster shutter
speeds in lower light.
LowerISOshavevaluesfrom 50 ISOandaremostlyused
for subjects where a higher-quality image is required –
wonderfulforuseinportraiture,wherethegreatestquality
of image is desirable.
HigherISOshavetypicalvaluesof 400 ISOand 800 ISO
andaremoresuitedtoworkwherethegrain(noise)would
notaffecttheoutcome.Howevernewercamerasarenow
becomingmoreandmoresophisticatedandsensitivesoas
nottohavesuchanissuewiththenoiselevels,evenwhen
shooting in lower light levels. On occasion when using
filmswithhigherISOsphotographerswouldmakeuseof
the grain (noise) for artistic and atmospheric effect.
However the digital grain equivalent (noise) is not
commonlyconsideredasaestheticallypleasingastheones
found on film, and as such would not be a desirable
outcome for most images.
Digitalsystemsnowenablethephotographertouseeven
higher ISOs than were originally available with film.
HowevertherealityisstillthatthehighertheISOvaluethe
greatertheamountofnoise(grain)and thelessdynamic
rangethatwillbepresentinthefinalimage,anditisforthe
photographertodecidewhetherthisisacompromisethey
would be willing to accept in an image.
Shutter Speed (exposure time)
Thisvariableisafairlysimpleconcepttounderstand–itis
simplytheamountoftimethatthefocalplaneisexposedto
light.Howevertherearecertainvaluesandsettingsthatthe