KAWARTHACAMERACLUB
BeginnersWorkshop WrittenbyGerryGerling
Welcometoourfirstbeginnersworkshop.Ifyouhavedoneyour
homeworkyouwillknowwheretogoonyourcameratoadjustthe
apertureandtheshutterspeed.Todaywewillexploretheeffectsof
apertureandshutterspeedandwewillalsotouchonlSO.
THEEFFECTSOFHOWAPICTUREIMAGEISRENDEREDONACAMERA'SSENSORWHENCONTROLLEDBYTHEAPERTUREANDSHUTTERSPEED
PICTURE
LIGHT
therightamountfor
aproperexposure
f/1.4
f/22
APERTURE
morelight
lesslight
1/2sec.
1/1000sec
SHUTTERSPEED
morelight
lesslight
LARGEAPERTURE
SMALLAPERTURE
SLOWSHUTTER
FASTSHUTTER
SHALLOWDOF
WIDEDOF
BLURMOVEMENT
FREEZEACTION
ISOLATESUBJECT,
BOKEH
MOSTEVERYTHING
INFOCUS
CREATIVE
NOBLUR
APERTURE
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Everylenshasanaperture.Itissometimesreferredtoasanfstop,f
steporlensopening.Ifsomeonespeaksofalensbeing"wideopen"
theyarereferringtothelenssetatitsmaximumaperture.Thereisan
adjustablediaphragminthelenswhichadjuststheaperture.
Thediaphragmopenstoletmorelightthrough,orclosestoreducethe
amountoflightcomingthrough.Ihavealenswithanadjustable
aperturewhichIwillpassaroundsoyoucanseethediaphragm.Turn
theapertureringfromf/4.5throughtof/32toseethediaphragmopen
andclosetocontrolthelight.
Youprobablyhaveneverseenthediaphragmonyourlensbecausethe
apertureinmostdigitallensesiswideopenatrest.Thisissothereis
themaximumamountoflightforyoutoseetheimageintheviewfinder
orLCDscreen.
Whenyoupresstheshutterbuttonthecamerawillinstantlystopdown
theaperturetothe*pre-setvaluejustbeforetheshutterisopened
thenthediaphragmwillopenagainaftertheshuttercloses.
(*Ihaveusedasterisksthroughoutthispresentationtoremindmewheretogivealittleextraexplanation.)
Theapertureisinfinitelyadjustableasyouwillhavenoticedonthelenswhich
Ipassedaroundbuttherearewhatwecallfullstopsandtheseare:f/1.4,
f/2.0,f/4.0,f/5.6,f/8,f/11,f/16,f/22,f/32.*
Theyarecalledfullstopsbecauseeachfullstopwilleitherdoubleorhalvethe
amountoflightwhichthediaphragmwillletthroughthelensdependingon
whetheryouaregoingupthescaleordown.
Forexamplef/5.6willletthroughexactlytwiceasmuchlightasf/8andf/22
willletthroughexactlyhalfasmuchlightasf/16.*
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Youmaywonderwhythereislesslightwithlargernumbersandmore
lightwithsmallernumbers.Thereisamathematicalexplanationfor
thisbutwewillnotgointothatnow.
Aneasywaytotrytounderstanditwouldbetomakeafractionofthef
stops,forexample,think1/8,forf/8and1/16forf/16.
Idon'trecommendthatyoualwaysrefertothemasfractionsbutitmay
makemoresensetoyoutothinkofthemassuch.Withalittle
experiencethenumberswillbecomesecondnature.
Somelenseshaveawideaperturesuchasf/2.8,f/1.8orevenf/1.4.
Thesearesometimescalledfastlensesandarealmostalwaysmore
expensivethanslowerlenses.Thesefastlensesusuallyhavealarge
frontelement(expensive)whichisrequiredtocapturethelarge
amountoflightwhichmakesthemfast.
Themaximumapertureofalensisreferredtoasthe'speed'ofthe
lens.*
Ifweseealensdesignationwhichreads:35mm1:1.8weknowthatit
isaprimelenswhichhasafocallengthof35mmandamaximum
apertureoff/1.8.*Prettystraightforwardright?
Nowanotherlensmayhaveadesignationof55-200mm1:4-5.6.Not
sostraightforward,buteasytounderstandonceyouknowhowtoread
it.55-200mmmeansthatitisazoomlens(notaprime)andthe
maximumapertureisf/4at55mmandf/5.6at200mm.
Generally,lensesarenottheirsharpestwideopenorclosedrightdown.
Thesweetspotusuallyisacoupleofstopscloseddownfromwide
open.Itwouldtakeaveryexperiencedeyetonoticethedifferenceso
don'thesitatetousethefullrangeofaperturesyourlensoffers.
THEEFFECTSOFAPERTUREONEXPOSURE(Insimpleterms)
Whentheapertureisopenedup,morelightisallowedtopassthrough
thelens.
Whentheapertureiscloseddown,lesslightisallowedtopassthrough
thelens.
DEPTHOFFIELD
DefinitionofDepthofField-Depthoffield(DOF)isthedistancein
frontofwhereyouhavefocusedtothedistancebeyondwhereyou
havefocusedwhereobjectsareacceptablysharp.
Asageneralrule,2/3oftheDOFwillextendbeyondthepointwhere
youhavefocusedand1/3infront.
THEEFFECTSOFAPERTUREONDEPTHOFFIELD
Whenopened,theaperturedecreasesthedepthoffieldandwhen
closeditincreasesthedepthoffield.Tosaythesamethingdifferently,
alargelensopeningwillgiveshallowerDOFandasmalllensopening
willgivebroaderDOF.Wewillseethisillustratedinthevideoatthe
endofthissession.
ShallowDOFwillmakeyoursubjectstandout.Usealargelensopening
sothesubjectwillbeinfocusandeverythingelsewillbeblurred.
Ifyouwanteverythinginyourlandscapescenetobesharpuseasmall
lensopeningtoattainthemaximumDOF.
Therearetwootherthingswhichaffectdepthoffield:
1.AtelephotolenswillgiveshallowerDOF;
awideanglelenswillgiveaverybroadDOF.
2.Thecloseryouaretothesubject,theshallowertheDOF;
thefurtherawayfromthesubjectthebroadertheDOF.
ThefollowingpicturesareexamplesofshallowDOF,bokehandwide
DOF.ThepictureofthetulipbudisshownasapoorexampleofDOF
becausetheforegroundandbackgroundaretoodistracting.
Nowthatweknoweverythingthereistoknowaboutaperturewecan
discussshutterspeed.
SHUTTERSPEED
Likeaperturewhichcontrolstheamountoflightreachingthesensor
andhasthesecondaryfunctionofcontrollingdepthoffield,
shutterspeedalsocontrolstheamountoflightreachingthesensorand
hasasecondaryfunctionoffreezingorblurringaction.
Shutterspeedcontrolstheamountoflight(thatpassesthroughthe
apertureandreachesthesensor)bythelengthoftimetheshutteris
heldopen.1/50sec.letsintwiceasmuchlightas1/100sec.Thisalso
representsa*fullstop.
Themostsignificantcaveatofshutterspeedselectionisblurred
picturesduetoaslowshutterspeedandtherearetwotypesofblurred
pictures.Oneisfromcamerashakeandtheotherisfromsubject
movement.
Camerashakeshouldbeavoidedatallcostbecauseeverythinginthe
picturewillbeblurred.Useafastershutterspeedoratripodifyou
can't*handholdthecamerawithoutmovingit.
Subjectmovementontheotherhandcanbegoodorbad.Badsubject
movementiswhenthesubjectmoveswhenyoudon'twantittoand
resultsinthepicturebeingspoiled.
Goodsubjectmovementisusuallydependantontheartistictalentof
thephotographer.Visualizeabatterhittingaballwherethebatteris
notblurredbuttheendofthebatandtheballareblurred(because
motionisfasterattheendofthebat).*
Thispicturegivesthefeelingofmotionwhereyouexpectitandisfar
moredramaticthanapicturewhereeverythingisfrozensharp.
Or,awaterfallpicturetakenwithaslowshutterspeedwillgivethe
waterasilkysmoothappearancewhileeverythingarounditwhichis
notmovingwillbe*sharp.
Panningamovingcarataslowshutterspeed(ifdoneright)willshow
thecarsharpandthebackgroundblurred,givingtheappearanceof
speed.
Whenpanning,youmustkeepthesubjectinthesameplaceinthe
viewfinderwhiletheshutterisopen.Bydoingso,thesubjectwillnot
appeartobemovingwithintheframebutthebackgroundwillbe
blurred.
Thenextpictureshowsthiseffect.
ISO
IsaidthatwewilljusttouchonISOtodaysoIwillbebrief.TheISO
numberisanindicationofhowsensitiveyourcamera'ssensoristo
light.
ItcanbemanuallysetoryoucanleaveitinAutoISOandthecamera
willbumpitupwhennecessary.IwillshowyouthetwoeffectsofISO
inthevideodemonstrationattheendofthesession.
Belowisthelinktothevideothatyoucangotoforpractice.
http://www.canonoutsideofauto.ca/play
AUTOMODE
WhenyousetyourcameratoAutoyouhavenocontroloverlens
opening,shutterspeedoranythingelse.ThecamerawillmakeALLthe
decisions.Noneoftheitemsyouselectedinthemenuwilltakeeffect,
itwillevenpoptheflashupifitthinksthereisnotenoughlightwhich
canbeveryannoying.(Yourgranddaughter'spoint&shootcameraor
smartphoneshootsinauto)
Nophotographerworthhisorhersaltwouldbecaughtdeadwiththeir
camerasettoAuto.Ifthereisnotareasontouseapertureorshutter
priorityuseProgrammedMode(P).Whenyouhaveyourcamerasetto
Ptheflashwillnotpopupunexpectedlyandeverythingthatyouhave
setinthemenuwillbeineffect.Thecamerawillstilldecidewhat
apertureandshutterspeedtouseandthisisagoodcompromise.
MANUALMODE
YounodoubthaveseentheletterMonthedialwhichyouusetoselect
apertureandshutterpriority.Thissettingallowsyoutosetboththe
shutterspeedandtheapertureforagivenpicture.Hey,thismaysound
greatbutYOUwillhavetoselectthecombinationofapertureand
shutterspeed*togivetheproperexposure.Notsogreatnoweh?
SufficeittosaythatMwillbeleftforanotherday(oryear)butIwill
touchonitbrieflyinthevideo.
INCONCLUSION
You,asthephotographermustdecidewhatyouwantyourpictureto
show.Forexample:
• Doyouwantasmuchofthepictureaspossibletobeinfocus?(Use
aperturepriority-asmalllensopeninggivesbroadDOF)
• Doyouwantthesubjecttostandoutandbeisolatedfromthe
background?(Useaperturepriority-alargelensopeninggives
shallowDOF)
• Doyouwanttocutdownthelightsothatyoucanuseaslow
shutterspeedandstillhavethepictureproperlyexposed?(Use
aperturepriority-asmalllensopeningreducestheamountoflight
passingthroughthelens)OR(Useshutterpriority-selectaslow
shutterspeedandletthecameraselectthesmallaperture)*
• Doyouwanttofreezeactionwithnoblur?(Useshutterpriority-a
fastshutterspeeddoesnotgiveenoughtimeforthesubjecttobe
blurred)
• Doyouwanttotakeapicturewithnosubjectorcamera
movement?(Useshutterpriority-afastshutterspeedwillfreeze
allmovement)
• Doyouwanttotakeapictureshowingsomeblurwherethereis
motion?(Useshutterpriority-a*Mediumshutterspeedwillonly
showblurinthefastestmovingparts)
IfyouwanttocontroltheshutterspeedsimplyselectShutterPriority
andthecamerawillselecttheaperturetogivetheproperexposure.
IfyouwanttocontroltheaperturesimplyselectAperturePriorityand
thecamerawillselecttheshutterspeedtogiveproperexposure.
Ifyoudon'thaveareasontouseApertureorShutterpriorityleavethe
selectoronP,neverAuto.
Soyousee,youcanputwhatyouhavelearnedtodaytouserightaway
andnothavetodreadgoingoutofAutomode.
*Andnowthatyouknowwheretogoonyourcameratomake
apertureandshutterspeedadjustmentsyouCANputyournewfound
skillstouse-rightnow.
Butremember,ifyoudon'tpracticewhatyouhavejustlearneditwill
besoonforgotten.Goodluck,andhappyshooting!
Diaphragmillustrationsfromwww.digitalphotographylive.com