Adamsays:Noisewasa term
originallyusedin radioreception
todescribeunwantedsignalor
‘s tatic’thatinstrumentspicked
up. It thenbeganto takeon a
broadermeaning,appliedto
anyunwanteddisturbancein
anelectricalsignal.Imagenoise
indigitalphotographygotits
namethisway.
Itappearsas aberrantpixels
thatlookoutof placein an
image,causedby electrical
fluctuationsin thesensorbeingmistakenas lightcomingin
fr omthelens.It rearsitsugly
head wheneveryou’reshooting
inlowlight,whereasbright
conditionsofferenoughlightto
drownoutthenoise.Youcan
thinkof thelightas a coloured
li quid,andthenoiseas a few
dropsof a differentcolour.Add
a coupleof dropsintotheocean
and it won’tchangethecolour,
but do thesamein a smallglass
oftheliquidandthecolour
will change.Therearea numberof ways
toreducenoise,andcamera
choiceplaysa part.Newer
sensorsaremuchbetterat
is olatingtheunwantedsignal,
sooffera muchcleanerimage.
Manycamerasnowalsohavea
lo ngexposurenoisereduction
functionthathelpsa greatdeal.
You shouldchooseto shooton
the lowestISOsensitivityyou
can forthelightingconditions,
asISOamplifiesthesignalbeing
recordedby yoursensor,and
thisincludesnoiseas wellas the
recordedlight.If thesignalis
mostlynoise,thentheamplified
si gnalwillbe mostlynoisetoo.
You canalsousePhotoshop
toreducenoise.It dealswiththe
two typesof noiseseparately- lu minosityandcolour.
Luminositynoiseis aberration
inthebrightness,whichwill
lo oklikespecksof lighterand
darkerpixels,whilecolournoise
isaberrationin thehueandwill
lo oklikespecksof colour.
I’mlookingto starta personalprojecton live
musicgigsbuta fewpeopleat my localcamera
clubhavewarnedme to keepmy eyeon noise
levels.I’veneverunderstoodhowan imagecanbe noisy.
Whatis imagenoise,andhowdo I dealwithit?
NoahThomas,SurreyHow do I reducedi gitalnoise inmy images?AboveNoisecomesin twodifferentflavours– luminositynoiseand
colournoise.Photoshopdealswitheachseparately.K now
Your Stuf fAll your technique and gear questions answered byour team of experts [email protected]68 PrAcTIcALPhOTOgrAPhYBen Hawkins
With over 17
years as a
photographic
journalist, Ben is
a pro competition
judge and writer.Adam Atkins
PP’s features
writer is an
accomplished
professional
sport and travel
photographer.Kirk Schwarz
As PP’s technique
andgeareditor
Ki rkknowsthe
bestkit,andhow
togetthemost
out of it.tip
Shoot
inRAW
Bycapturinga RAWfile, you
canthenusethepowerful
noisereductionsliders in
AdobeCameraRaw
duringtheedit.Luminosity noise CoLournoiserocco dipoppa