Digital SLR Photography - UK (2019-12)

December 2 019 DigitalSLR Photography 49

There’sa dialoguebetweenexperienced

photographersthatcansoundlikeaforeign

languagetonewcomerstoaperturecontrol.

Let's havea lookat translatingpopular

terminologytousingapertures.

BOKEH(BO-KEH):Thenameforpleasantly

blurredareasofanimage createdbyusinga wide

aperturetoprovideveryshallowdepth-of-field.

Somelenseshaveroundedorextrabladesto

givea morepleasing'bokeh'orblureffect.

FASTLENSES:It’sa termusedtoreference

lenseswithafasterthanaveragemaximum

aperture,typicallyf/1.8orfasterforprimesor

f/2.8forzooms.Fastlensesareusuallyprimes,

premiumzoomsorpowerfultelephotos.

DEPTH-OF-FIELD:Thinkofyourimageas

beingthree-dimensional, nottwo-dimensional,

withdepthstretchingthroughthe scene.

Depth-of-fieldreferstotheextentofsharpness

in thescene.Shallowdepth-of-fielddeliversa

smallzoneofsharpnesswithlotsof‘bokeh’;

narrowdepth-of-fieldmaximisessharpness

throughoutthe sceneandis mostcommonly

usedin landscapesforfront-to-backfocus.

F/STOPS:Theseareyourapertures,rangingin

incrementsfromf/1.8tof/ 32 (orsimilar),which

youselectviayourcameratovarytheamountof

lightreachingthesensoranddepth-of-field.

Smallapertureshavelarge f/stops(e.g. f/16);

wideapertureshavesmallf/stops(e.g.f/1.8).

OPENTHEAPERTURE:Whenyouopenthe

aperture,you’reselectinga largef/stop(e.g.f/1.4

orf/2.8).Openingtheapertureallowsmorelight

topassthroughthelens,resultinginimages

displayinga shallowdepth-of-field (along with

increasingtheshutterspeed).

CLOSINGTHEAPERTURE:Obviously,thisis

theoppositeofopeningtheapertureand

involveschoosinga mid(f/8-f/11)tosmall

(f/16-f/32)aperturesettingthatletthroughless

lightandworkstoincreasedepth-of-field(as

wellasgivinga slowershutterspeed).

SWEETSPOT:Everylenshasa ‘sweetspot’, an

aperturethatdeliversmaximumsharpnessand

minimaldistortionssuchasdiffraction.Typically

this is somewhere betweenf/8 tof/ 11.

THEFUNDAMENTALSOFF/STOPS

IRE

NA

RIH

OVA

/SHU

TTE

RST

OC

K

DEZY

/SHU

TTE

RSTOCK

Above:Lensesoffer a maximum aperturearoundf/2.8 but

faster versions are available, with the minimum aperture usually

around f/32. The sharpest images are usually around f/8 to f/11.

PhotoMasterclass

JARGON BUSTER

As youchangeyourapertureby onestop,youare
eitherhalvingordoublingtheamountoflightpassing
throughthelens. Hereyoucanseethemainf/stops
thataffectexposurebyonefullstop.However,almost
allcamerasallowyoutoadjusttheexposurein 1/2or
1/3-stopincrements.Forinstance,betweenf/2.8and
f/4you'llfindyoucansetf/3.5if using1/2-stops,or
f/3.2andf/3.5whenusing1/3stops.If thisgetstoo
confusingforyou,it’sbesttomemorisethefull-stop
settings andshootsequencesat 1/2-stopincrements
untilyoufamiliariseyourselfwiththef/ numbers.
Onceyou'vedonethis,switchthecamera'ssettings so
thatit allowsyoutochange theaperturein1/3-stop
increments(viathecamera'sCustomFunction
settings)andrepeatthelearningprocess.
Mostopticsareidentifiedbytheirmaximum
aperture,forinstancethe50mmf/1.2offersa widest
aperturesettingoff/1.2.Mostzoomshavea variable
maximumaperturethatchangesasyoualterthefocal
length.Forinstancethe18-55mmf/3.5-5.6hasa
maximumapertureoff/3.5at 18mm,butthisstops
downtof/5.6 as you zoom towards 55mm.

F/1.8

F/4

F/11

F/2.8

F/5.6

F/22