BasicCameraControls

Thebasiccontrolsonallcamerasaresimilar,helpingyoutoperformthesameactionseverytimeyoutakeapicture.You'llneedtoseethesceneyouarephotographing,decidehowmuchofityouwanttoinclude,focusitsharplywhereyouwantittobesharp,andusetheshutterspeed(thelengthoftimetheshutterremainsopen)andaperture(thesizeofthelensopening)toexposethefilmorsensortothecorrectamountoflight.Oneofthemostpopularcameratypesisshownherethesingle-lensreflex.Otherbasiccameradesignsaredescribedlaterinthischapter.Asthecamera'ssettingschange,thepicturechangesalso.Whatwillascenelooklikeatafastershutterspeedoraslowerone?Howdoyoumakesurethebackgroundwillbesharporoutoffocusifyouwantitthatway?Onceyouunderstandhowthebasiccameracontrolsoperateandwhatyourchoicesare,youwillbebetterabletogettheresultsyouwant,ratherthansimplypressingthebuttonandhopingforthebest.

DatapaneldisplaysISO,shutterspeedandaperturesettings,numberofexposuresremaining,andotherinformation.

Modedialtosetmanualoroneofseveralchoicesofautomaticoperation

Memorycard(insidethecamera)storestheimage.

monitordisplaysstoredimagesandmenusforcamerasettings.DIGITALCAMERAAnarrayofcontrolsonthissingle-lensreflexdigitalcameraletsyoumakesettingsmanuallyorautomatically,andview(anddeleteifyouwish)thephotographyouhavejustmadeoranyothersonitsmemorycard.

Apertureselector

Controldialformanuallyselectingshutterspeedand/oraperture.

Modedial

Focusingringformanuallyfocusingthelens.

Focusingring

MANUALFILMCAMERAManuallyadjustedcontrolsonthis35mmsingle-lensreflexcameraletyousettheshutterspeed(thelengthoftimetheshutterremainsopen),selectthelensaperture(thesizeofthelensopening),focusonaparticularpartofthescene,andchangefromonelenstoanother.

16ICamera

Interchangeablelens

AUTOMATICFILMCAMERAOnautomaticcameras,controlkeysoftenreplaceadjustableknobsorrings.Thismodelautomaticallyadjuststhefocus,shutterspeed.aperture,andlensfocallengthandfiresabuilt-inflashwhennecessary.Youcanoverridetheautomaticfeaturesifyouwanttoadjustthecamerassettingsyourself.

Switchforselectingmanualorautofocus.

Theviewfindershowsyou-theentirescenethatwillberecordedandindicateswhichpartofthesceneisfocusedmostsharply.Theviewfinderusuallydisplaysexposureinformationheretheshutterspeed(1/250)andaperture(f/16).

Theshutter-speedselectorcontrolsthelengthoftimethattheshutterremainsopen.Ashortertimedecreasesthelikelihoodthatamovingobjectwillappearblurred.

Largeapertoreopening

Smallapertureopening

Theapertureselectoradjuststhesizeofthelensopeningcreatedbythebladesofthediaphragm.Thesmallertheapertureopening,thegreaterthedepthoffield(thepartofthescenefromneartofarthatwillbesharp).

Long-focal-lengthlen$

Interchangeablelensesletyouselectthelensfocallength,whichcontrolsthesizeofobjectsinthepictureandtheextentofthescenethatwillberecordedonthefilmorcaptureddigitally.

ChapterTwo|17

TheShutterTheShutterandLight

Twocontrolsadjusttheamountoflightthatreachesthesensororfilm:theshutter,describedhere,andtheaperture(pages24-25).Thecombinationofanapertureandashutterspeedisanexposure,whichmustbeacorrectonesoyourpictureisneithertoolightnortoodark.Adjustingthelengthoftimetheshutterremainsopencontrolstheamountoflightthatreachesthelight-sensitivesurface.Doublingtheamountoftimeitisopengivesonestopmoreexposuretwicetheamountoflight.Halvingtheamountoftimegivesonestoplessexposurehalftheamountofhght.Eachfullstopshuttersettingishalf(ordouble)thetimeofthenextoneandismarkedasthedenominator(bottompart)ofthefractionofasecondthattheshutterremainsopen:1(1/1oronesecond),2(1/2second),4(1/4second),andsoonthrough8,15,30,60,125,250,500,1000orhigher.Somecamerashaveshuttersthatreach1/8,000ofasecond.B(bulbsetting)keeps'theshutteropenaslongasthereleasebuttonishelddown.T(timesetting)opens

theshutterwithonepressoftherelease,andclosesitwithanother.Electronicallycontrolledshutterscanoperateatanyspeed,forexample,1/38second.These"stepless"speedsaresetbythecamerainautomaticexposureoperation;somecamerasallowyoutodialtheminyourselfothersdon't.Somedigitalcamerasuseashutterforexposure.Othersusethemonlytoblocklightwhenthesensorneedsdarkness;theycontrolexposurebyturningthesensoronandoffforaprecisely-timedduration.NOTE;Theterm"stop"inphotographyreferstoachangeinillumination,whethertheshutterspeedortheapertureischangedtoachieveit.Togiveonestopmoreexposuremeanstodoubletheamountoflightreachingthefilmeitherbydoublingtheexposuretimeorbydoublingthesizeoftheaperture(seepage25).Togiveonestoplessexposuremeanstocutthelightreachingthefilminhalfbyhalvingtheexposuretimeorbyhalvingthesizeoftheaperture.

SHUTTERSPEEDSWHATYOUSEEANDWHATYOUGETCamerasusedtoprovideshutterspeedsonlyInfullstops.OldermechanicalshutterscouldonlyprovideamodestnumberofsettingssotheyweremadeonlytoletinlightfordoubletheamountoftimeoftheshutterspeedbeforeItorhalfthatoftheoneafterit.Camerastodaywithelectronicallycontrolledshutterswillalsosetshutterspeedsinbetween.Mostcamerasdisplayincrementsofone-halforone-thirdstopsandallowyoutochoosewhichofthoseyousee.Thischartshowshowlongeachfullstopremainsopen,plushowyourcameramaydisplayfractionalstops.Manyofthesenumbersareroundedoff.Don'tbesurprisedbyinconsistencyinshutterspeedsamongcameramanufacturers.Forexample,anexacthalf-stopsettingbetween1and2shouldbethesquarerootoftwo,approximately1.4142.Onecameradisplaysthisas1.4,anotheras1.5.NOTE:Don'tconfuse2,meaning2seconds,with2,meaning1/2second;4,meaning4seconds,with4,meaning1/4second,andsoon.Ifyourcameraallowsyoutochooseamongdifferentwaystosetshutterspeeds,usefullstopswhilelearningphotography.Dothesamewithaperturesettings(seepage24).ActualtimeShutterspeedsyourcameramaydisplayinsecondsFULLSTOP1/3STOP1/2STOP1sec1111.31.51.61/2sec2222.5331/4sec444

WHERESHUTTERSPEEDSETTINGSAREDISPLAYEDONVARIOUSCAMERAS

Inthecamera'sviewftnderOntheshutter-speeddialInthedata-panelreadout

Fortheaboveexamples,eachcameraisselto1/500sec.Noticethaithecameradisplaysonlythebottomnumberofthefraction.

18ICamera

5661/8sec8881011131/15sec1515152020251/30sec3030304045501/60sec60606080901001/125sec1251251251601802001/250sec2502502503203504001/500sec500500500

HOWSHUTTERSWORK

Leafshutter

Film

Aleaforbetween-the-lensshutterisgenerallylocatedinsidethelensitself.Allviewcameras,manymedium-formatcameras,andmostpoint-and-shootsuseleafsliutters.Theleafshutterconsistsofanumberofsmalloverlappingmetalblades.Asshownatright,whentheshutterisreleased,thebladesopenupforanamountoftimedeterminedbytheselectedshutterspeed,thenshutagain.Thetotalamountoflightadmittedduringthiscycleproducesthefullyexposedphotograph(seetopofthepage).ManycompactdigitalcamerasuseaparticularkindofCCDsensor(calledinterlinetransfer)thatcontrolsthelengthofexposureelectronicallyMostofthesehavealeafshutterthatisnormallyopen,butclosesmomentarilybeforeexposuretoallowthesensortoinitialize,Advantages/Disadvantages.Aleafshutterisquieterthanafocal-planeshutterandcanbeusedwithflashatanyshutterspeed.Butsincetheleafshutterhastoopen,stop,andthenreversedirectiontocloseagain,mosthavetopspeedsnohigherthan1/500second.Ifyourinterchangeable-lenscamerausesleafshutters,theshutterisprobablybuiltintothelens.Thecostofashutterthenaddstothepriceofeachlens.Also,actualshutterspeedsmightbealittleslowerorfasterthaneachother.Generally,thedifferenceissmall,butitcouldbeenoughtomakeanoticeabledifferenceinexposurewhenchangingfromonelenstoanotherBecausealeafshutteronlyhastoopenuntilitreachestheouteredgeoftheaperture,manycamerascansetahighershutterspeedforsmallaperturesthanforlargeones.Leafshuttersaresoquietthatmanycompactdigitalcamerasareprogrammedtoemitanelectronicshutter-likesoundwhenthebuttonispressedsotheusercantellwhenanexposurehasbeenmade.

Afocal-planeshutterisbuiltintothecamerabodyandislocateddirectlyinfrontofthesensororfilm;itconsistsoftwooverlappingcurtains.Whentheshutterisreleasedatslowshutterspeeds,thefirst(opening)curtainmovesacrosstheframe,revealingawindowthroughwhichthesensororfilmisexposed.Theshutterwaitsforthecorrectamountoftime,thenitclosesthesecond(following)curtaintostoptheexposure.Athighershutterspeeds,thefollowingcurtainbeginstoclosebeforetheopeningcurtainhascompleteditstravel.ThefilmorsensorIsexposedthroughwhatappearstobeamovingslit.Astheshutterspeedincreases,thisslitnarrows.Theseriestotherightshowstheshuttertravelatfastshutterspeeds.Thenarrowslitexposesonlypartoftheframeatanyonetime,buteverypartofthefilmorsensorreceiveslightforthesameamountoftime.Above,seetheeffectoftheentireexposure,withailsectionsofthefilmorsensorhavingreceivedtheproperamountoflight.Theshuttershownheremovesfromsidetoside.Somecamerashaveanothertypeoffocal-planeshutter(calledaguillotine)thatmovesfromtoptobottom.Somedigitalsingle-lensreflexcamerasuseaninterlinetransferCCDsensor(seetextatleft).Theyalsohaveafocal-planeshutterbutdonotuseittocontrolthelengthofexposure.Advantages/Disadvantages.Interchangeablelensesforacamerawithafocal-planeshuttercanbelessexpensivethanthoseforcamerasrequiringleafshutters,sinceashutterdoesnothavetobebuiltintoeachlens.Andfocal-planeshutterscanreachhigherspeedsthanleafshuttersashighas1/8000sec.Generally,however,youcan'tuseelectronicflashwhenbothshuttercurtainsaremovingatthesametime,Thehighestshutterspeedatwhichtheopeningcurtainhascompleteditstravelbeforethefollowingcurtainbeginstomovecalledsyncspeedmaybeasslowas1/60second.Atanyfastershutterspeedthanacamera'ssyncspeed,aflashwillilluminateonlythesliceoftheframerevealedbytheslitatthemomenttheflashistriggered.Becauseyoumustusearelativelyslowshutterspeedwithflash,existing(orambient)lightmayregisteronthefilmorsensoraswellaslightfromtheflash.Thiscanleavea"ghost"orsecondimageinthepicture.

ChiapterTwo|19

TheShuttercontinuedTheShutterandMotion

Thefastertheshutterspeed,thesharperamovingsubjectwillbe.Ablurredimagecanoccurwhenanobjectmovesduringanexposure,becauseitsimageprojectedontothesensororfilmbythelenswillmoveduringthetimetheshutterisopen.Iftheobjectmovesswiftly,oriftheshutterisopenforarelativelylongtime,thismovingimagewillblurandbeindistinct.Butifyouincreasetheshutterspeed,youcanreduceoreliminatetheblur.Youcancontrolthiseffectanduseittoyouradvantage.Afastshutterspeedcanfreezeamovingobject,showingitspositionattheinstantofexposure(seeoppositepage).Youcanuseaslowershutterspeedtoincreaseblurringandaccentuatethefeelingofmotion(seepages22and23).Generally,theamountofmotionblurwilldoubleifyouincreasetheshutterspeedbyonestop(towardalongertime).Shownbelowaretheeffectsofvaryingshutterspeedandcameramovement.Inthepictureatfarleft,thebicyclemovedenoughduringarelativelylongexposureof1/30secondtoleaveabroadbluronthe

film.Inthenextphotograph,atashutterspeedof1/500second,thebicycleismuchsharper.Amovingsubjectmayvaryinspeedandthusaffecttheshutterspeedneededtostopmotion.Forexample,motionslowsandsometimesstopsatthepeakofamovementthatreverses,suchasthepeakofajumpjustbeforedescent(oppositepage),andevenarelativelyslowshutterspeedwillrecordtheactionsharply.OtherfactorsbesidesshutterandsubjectspeedalsoaffecttheamountofblurringInaphotograph.Whatmattersishowfaranimageactuallytravelsacrossthefilmorsensorduringtheexposure.Inthephotographbelowoftheridermovingdirectlytowardthecamera,thebicycle'simageremainsinvirtuallythesamepositionintheframe.Thusthereisfarlessblurringevenat1/30second.Asubjectclosetothecamerathatismovingslowly,suchasacyclist10feetaway,willcrossmoreofthefilmorsensorandappeartoblurmorethanthesamesubjectmovingatthesamespeedbutfartheraway.Along-focal-lengthlensmagnifies

objectsandmakesthemappearclosertothecamera.Amovingsubjectwillappearmoreblurrywhenphotographedwithalonglensthanitwouldifphotographedwithanormallensusedatthesamedistance.Panningkeepsamovingsubjectsharpwhileblurringthebackground.Inthepicturebelow,right,thecamerawasmoved(panned)inthesamedirectionthebicyclewasmoving.Sincethecameramovedalongwiththebicycle,theriderappearssharpwhilethemotionlessbackgroundappearsblurred.Successfulpanningtakesbothpracticeandluck.Variablessuchastheexactspeedanddirectionofthemovingobjectmakeitdifficulttopredictexactlyhowfasttopan.Decidewhereyouwanttheobjecttobeatthemomentofexposure,startmovingthecameraafewmomentsbeforetheobjectreachesthatpoint,andcontinuethemotionaftertheexposure(follow-through)asyouwouldwithagolfortennisstroke.Thelongerthefocallengthofthelens,thelessactualcameramovementwillbenecessary.

DIRECTIONOFAMOVINGOBJECTAFFECTSTHEAMOUNTOFBLUR1/30second1/500second

1/30second

1/30second,camerapanned

Whenasubjectistravelingparalleltotheplaneofthefilmorsensor,considerablemovementislikelytoberecordedonthefilm.Thesubjectwillbeblurred,unlesstheshut

fthesubjectismovingdirectlytowardora>vayfromthecamera,nosidewaysmovementisrecordedsoaminimumofblurisproduced,evenatarelativelyslowshutterspeed.

terspeedisfast.

20ICamera

Duringpanning,thecameraismovedinthesamedirectionasthesubject.Theresultisasharpsubjectandablurredbackground.

SHUTTERSPEEDSTOSTOPACTIONPARALLELTOTHEIMAGEPLANE

TypeofMotionSpeedCamera-to-SubjectDistance

Z5feet50feet100feet

Veryfastwalker(5mph)1/1251/601/30

Childrunning(10mph)1/2501/1251/60

Goadsprinter(20mph)1/5001/2501/125

Speedingcar(50mph)1/10001/5001/250

Airplane-1/1000

LIFFORDOTOSlamDunk,1990Motionslowsatthepeakofanactionthatreverses,suchasthisleapintotheair.Atthatmomentofslowermovement,theshutterspeeddoesn'thavetobeasfasttoshowthemotionsharply.Heretheboyjumpsfromanoverturnedgarbagecanforaslamdunk.Thekeywordinphotographingactionisanticipation.Whatdirectionisthesubjectmoving?Whereshouldyoubefocused?Whenmightaninterestingmomentoccur?Thinkaboutwhatisgoingtohappen,ratherthantryingtocatchuptowhathasalreadyhappened.

ChapterTwo|21

TheApertureTheApertureandLight

NUBARALEXANIANPattyLarkin,Philadelphia,1994Afastlens,onethatopenstoawideaperture,isusefulindimlight,suchasindoors.Awideapertureletsyousetashutterspeedfastenoughsothatyoudon'Ihavetouseatripodtokeepthecamerasteady.Itisalsousefulwhenphotographingactionbylettingyoushootatafastenoughshutterspeedtoshowmovingsubjectssharply.

F-STOPS:CONTROLLINGTHESIZEOFTHELENSAPERTURELensescomewithalimitedrangeofapertures(f-stops)usuallymarkedinfullstopIncrements.EachfullstopletsInhalftheamountoflightastheonebeforeitanddoublethatoftheoneafterit.(Notethatthesmallerthef-number,thelargerthelensopening.)Aperturesarecontinuouslyvariable;onmanycamerastheycanbesetanywhereinbetweenfullstops.Butyourlensordisplaymayonlyindicateone-halforone-thirdstopincrements.Thischartshowsarangeoffullandfractionalapertureopenings.Notallcamerasnumberthefractionalaperturesexactlyasshown.Ifyourcameraallowsyoutochooseamongdifferentwaystosetapertures,usingfullstopswillbelessconfusingwhileyoulearnphotography.Aperturesinfull1/21/3stopsstopstop

Theaperture(thesizeofthelensopening)controlsthebrightnessofthelightthatreachesthesensororfilm.Theapertureworkslikethepupilofaneye,enlargingorcontractingtoadmitmorelightorless.Inacameralens,thediaphragmaringofthin,overlappingmetalleaveslocatedinsidethelensisthemechanismthatcontrolsthesizeoftheaperture.Itsmovableleavescanbeopenedwidetoletinmorelightorcloseddowntoletinless(seeopposite).Thesizeofanapertureisindicatedbyitsf-numberorf-stop.Onearlycamerastheaperturewasadjustedbyindividualmetal"stop"platesthathadholesofdifferentdiameters.Thetermstopisstillusedtorefertotheaperturesize,andalensissaidtobe"stoppeddown"whenthesizeoftheapertureisdecreased.Partofthestandardized,full-stopseriesofnumbersonthef-stopscaleisshowninthebox,right.Thesmallernumberscorrespondtothelargerapertures,andadmitthemostlight.Eachlarger-numberedfill!f-stop(showninboldface)admitshalfthelightoftheprevious

Thefull-stopnumberscontinueinbothdirections.Widerapertures,forexamplef/Iorf/0.7,arepossiblebutsuchlensesaretooexpensiveforgeneraluse.Smalleronesf/32,f/45,f/64,f/90areseenonlyonspecializedlenses.Thechangeinlightoverthefullrangeoff-stopsislarge;alenswhoseapertureisstoppeddowntof/64admitslessthan1/4000ofthelightthatcomesthroughalenssetatf/1.Fewlensesprovidearangeofaperturesgreaterthaneightstops.Ageneral-purposelensforasingle-lensreflexcamera,forexample,mightrunfromf/1.4tof/I6.Acameralensdesignedforalargeviewcameramightstopdowntof/64butopenuponlytof/5.6.NOTE:Thewidestpossibleapertureonyourlensmaynotbeastandardfullstop.Alens'sf-stopsmaybeginwithasettingsuchasf/1.2,f/3.5,orf/7.7,thenproceedfromthenextfullstopinthestandardsequence.Lensesareoftendescribedasfastorslow.Thesetermsrefertothewidthofthemaximumapertureforthelens.Alensthatopens

f/1.4

f/2

f/2.8

f/4

f/5.6

f/8

f/11

f/16

f/22

f/1.4f/1.7

f/2f/2,3

f/2.8f/3.4

f/4f/4.7

f/5.6f/6,7

f/8f/9.5

f/11f/13

f/16f/19

f/22f/Z7

f/1.4f/1.6f/1,8f/2f/2.2f/2.5f/2.8f/3.2f/3.5f/4f/4.5f/5f/5.6f/6.3f/7.1f/8f/9f/10f/11f/13f/14f/16f/18f/20f/22f/25f/28

one.Alensthatissetatf/4admitshalfasmuchUghtasonesetatf/2.8andonlyaquarterasmuchasonesetat172.(Noticethatf-stopshavethesamehalfordoublerelation-sliipthatflill-stopshutter-speedsettingsdo.)

24ICamera

tof/1.4openswiderandissaidtobefasterthanonethatopensonlytoill.Fasterlensesallowyoutoshootmoreeasilyinlowlightorathighershutterspeeds.Theyalsoaremoreexpensivethanslowerlenses.

Thesizeofthelensopeningtheapertureorf-stopcontrolstheamountoflightthatpassesthroughthelens.Thelensshownherehas

WHEREAPERTURESETTINGSAREDISPUYEDONVARIOUSCAMERAS

aperturesfromf/2,8tof/22.Eachsettingisonestopfromthenext;thatis,eachletsintwiceasmuchlightasthenextsmalleropening,halfasmuchlightasthenextlargeropening.Thehigherthef-stopnumber,thesmallerthelensopeningandthelesslightthatisletin.Onthislens,f/2,8isthelargestopeningandletsinthemostlight.Asthenumbersgetbigger(4,5.5,8),theaperturesizegetssmallerandtheamountoflightadmitteddecreases,

Twiceasmuchlightasf/4

Halfasmuchlightasf/2.STwiceasmuchlightasf/5.6

Halfasmuchlightasf/4Twiceasmuchlightasf/S

Halfasmuchlightasf/5.6Twiceasmuchlightasf/11

Halfasmuchlightasf/8Twiceasmuchlightasf/16

Onthelensbarrel

NOTE:Somelensbarrelsnolongerdisplaytheaperturesasshownabove.Ratherthantwistingaringonthelenstosettheaperture,youdialinthesettinganthecamerabody.Regardlessofhowyouchangetheaperture,though,youarestillchangingthesizeofthelensopeningandthustheintensityoflightthatstrikesyourfilmorsensor.

Halfasmuchlightasf/11Twiceasmuchlightasf/2Z

Halfasmuchlightasf/16

ChapterTwo|25

TheAperture___conTheApertureandDepthofField

LARGEAPERTURE,LESSDEPTHOFFIELD

Thesmallertheaperturesize,themorethatascenewillbesharpfromneartofar.Astheapertureisstoppeddownandgetssmaller,moreofthebackgroundandforegroundinagivenscenebecomessharp.Theareaofacceptablesharpnessinapictureisknownasthedepthoffield.Thetwolargerphotographsshownonthesepagesweretakenunderidenticalconditionsbatwithdifferentaperturesettings,inthephotographabove,thediaphragmwasopenedtoitswidestaperture,f/2,andthelenswasfocusedontheboy(b)aboutsevenfeetaway(seesideviewofphotographerDuaneMichalsandhissubjects,aboveright).Theresultingphotographshowsashallowdepthoffield;onlythemiddleboy(b)issharp,whileboththeboyinfront(a)andthemanbehind(c)appearoutoffocus.Usingasmallaperture,f/16,givesadifferentpicture(oppositepage).Thelensisstillfocusedonthemiddleboy,butthedepthoffieldhasincreasedenoughtoyieldsharpimagesoftheotherfiguresaswell,Sometypesofcamerasletyouseetheextentofthedepthoffield.Withaviewcamera,youlookdirectlythroughthelens.Asthelensisstoppeddown,theincreasingsharpnessisvisibleontheground-glassviewingscreen.Asingle-lensreflexcameraalsoallowsyoutolookdirectlythroughthelens.Butmostmodels,regardlessofwhichapertureisselected,willautomaticallyshowthescenethroughthewidestaperture.Theyaredesignedthiswaybecauselookingthroughthelensatitswidestaperturegivesyouthebrightestpossibleviewforframingandfocusing.

26jCamera

Depthoffieldistheareafromneartofarinascenethatisacceptablysharpinaphotograph.Astheaperturechanges,thedepthoffieldchangestoo.Ifyourlenshasadepth-of-fieldscale(manydonot),youcanuseittoestimatetheextentofthedepthoffield.Onthislens,thebottomrowshowsSheaperture(f-stop)towhichthelensisset.Thetopringshowsthedistanceonwhichthelensisfocused.Thepairednumbersonthemiddleringcorrespondtof-stopsandshowtheneare.'itandfarthestdistancesthedepthoffieldcoverswhenthelensissetatvariousf-stops.Here,thelensissettoitswidestaperture,f/2,andfocusedonthemiddleboy(seesideviewofsceneabove),whoisatadistanceof7ft.Thedepthoffieldextendsfrommorethan6fttolessthan8ft:onlyobjectswithinthaidistancewillbeacceptablysharp.Ifdepthoffieldisshallow,asitishere,alenscanbesharplyfocusedononepointandstillnotproduceapicturethatissharpenoughoverall.

Whenthelensisstoppeddowntoitssmallestaperture,heref/16,thedepthoffieldincreases.AImosttheentiresceneeverythingbetweenabout5ftand3ftisnowsharpatthesamefocusingdistanceof7ft.NOTE;Thebiggerthef-stopnumber,thesmallerthelensopening(youcanseethisillustratedonpage25);f/!6isasmalleraperturethanf/2.

Lookingthroughthewidestaperturealsomeansyouseethescenewiththeleastpossibledepthoffield.Somecamerasprovidedepth-of-fieldpreviewbuttonthatstopsdownthelenssothattheviewfinderimageshowsthedepthoffieldattheapertureyouhaveselected.However,stoppingdownthelensreducesthebrightnessoftheviewfinderimage.Indimlightorataverysmallaperture,thatimagemaybecometoodarktobeseenclearly,butsingle-lensreflexfilmcamerasandviewcamerasdogiveyouawaytocheckdepthoffieldvisuallyatallapertures.Withadigitalcamerayoucanmake(andlaterdelete)atestshottoevaluatedepthoffieldfromthemonitordisplay.Othercameradesignsshowthescenedifferently.Rangefinderandsomepoint-and-shootdesignshaveawindowinwhichyouframeyourshot.Throughthisviewfinder,objectsatalldistancesappearequallysharp.Somelenseshaveadepth-of-fieldscalefromwhichyoucanestimatethedepthoffield.Thisscaleisprintedonthelensaspairednumbersthatbracketthedistancesofthenearestandfarthestpointsofthedepthoffield.Asthelensisfocusedandthef-stopset,thescaleshowsapproximatelywhatpartofthepicturewillbeinfocus.(Seethelensesatleft.)ThefarthestdistancemarkedonthelensappearsasthesymbolWhenthisinfinitymarkappearswithinthedepthoffieldshownonthescale,allobjectsbeyondtheclosestdistanceinfocuswillbesharp,

ChapterTwo|27

llSFQ-F"'=LiOTECa

2auci.ZI);

k04192

UsingShutterandApertureTogether

F

Bothshutterspeedandapertureaffecttheamountoflightenteringthecamera.Togetacorrectlyexposedpicture(onethatisneithertoolightnortoodark),youneedacombinationofshutterspeedandaperturethatletsintherightamountoflightforaparticularsceneandparticularISOspeed.Equivalentexposures.OnceyouImowacombinationofshutterspeedandaperturethatwillletintherightamountoflight,youcanchangeonesettingaslongasyouchangetheotherintheoppositeway.Whenusingfullstops,eachaperturesettingletsintwiceasmuchlightasthenextsmalleropening(larger-numberedsetting).Eachshutterspeedletsintwiceasmuchlightasthenextfasterspeed.(Seephotographsatright.)Youcanusealargerapertureifyouneedafastershutterspeed,oryoucanuseasmallerapertureifyouwantaslowershutterspeed.Thesameamountoflightisletinbythecombinationoff/16apertureata1/8-secondshutterspeed,asbyf/11at1/15second,andsoon.Thisback-and-forthbalanceiscalledareciprocalrelationship.Shutterspeedandaperturealsoaffect

ABUCKETOFLIGHTThequantityoflightthatreachesthefilmorsensorinsideacameradependsonbothaperturesize(f-stop)andexposuretime(shutterspeed).Howlongdoesittaketofillabucketwithwaterflowingfromafaucet?Thatdependsonhowwidethefaucetisopenandhowlongthewaterflows.Ifthewide-openfaucetfillsthebucketin2seconds,thenthesamebucketwillbefilledin4secondsfromahalf-openfaucet.Butregardlessofhowlongittakestofillthebucket,thebucketalwaysholdsthesameamountofwaterFilmanddigitalsensorsarelikethesebuckets.Tobeproperlyfilledwithlight(exposed),each

sharpness,butactdifferently.Shutterspeedaffectsthesharpnessofmovingobjects;apertureaffectsdepthoffield,sharpnessfromneartofar.Theirdifferenteffectsareshowninthethreephotographsatright.Ineach,thelenswasfocusedonthesamepoint,andshutterspeedandaperturesettingswerebalancedtoadmitthesametotalamountoflightintothecamera.Buttheequivalentexposuresresultedinverydifferentphotographs.Inthefirstpicture,asmallapertureproducedconsiderabledepthoffieldthatrenderedbackgrounddetailssharply.However,theshutterspeedneededtocompensateforthistinyaperturehadtobesoslowthattherapidlymovingflockofpigeonsappearsonlyasindistinctghosts.Astheaperturewassetwiderandtheshutterspeedfasterinthemiddlephoto,thebackgroundislesssharp,butthepigeonsarevisible,thoughstillblurred.Atfarright,astilllargerapertureandfastershutterspeedsacrificedalmostallbackgrounddetail,butthebirdsarenowveryclear,withonlyafewwingtipsstillblurred.

alwaysrequiresthesameamountthesamenumberof"gallons"oflight.Ifthecorrectexposureforasceneis2secatf/4,yougetthesametotalamountofexposurewithtwicethelengthoftime(nextslowershutterspeed)andhalftheamountoflight(nextsmalleraperture)4secatf/5.5.

Comparedtothetopillustration,thesameamountofwaterisdeliveredwhenhalfthevolumeofwaterrunsfortwicethelengthoftime.

28ICamera

QO

Smallaperture(deepdepthoffield),slowshutterspeed(motionblurred).Inthisscene,asmallaperture(f/16)producedgreatdepthoffield;thenearestpavingstonesaswellasthefarthesttreesaresharp.Buttoadmitenoughtighl,aslowshutterspeed(1/8sec)hwneeded;itwastooslowtoshowmovingpigeonssharply.Italsomeantthatatripodhadtobeusedtoholdthecamerasteady.

Equivalentexposures.Eachcombinationhereoff-stopandshutterspeedproducestheequivalentexposure(letsinthesameamountoflight)butproducesdifferencesindepthoffieldandmotion.

Mediumaperture(moderatedepthoffield),mediumshutterspeed(somemotionLargeaperture(shallowdepthoffield),fastshutterspeed(motionsharp).Afastsharp).Amediumaperture(f/4)andshutterspeed(1/125sec)sacrificesomeshutterspeed(1/500sec)stopsthemotionofthepigeonssocompletelythatthebackgrounddetailtoproducerecognizableimagesofthebirds.Buttheexposureisflappingwingsarefrozen.Butthewideaperture(f/2)neededgivessolittledepthstilltoolongtoshowthemotionofthebirds'wingssharply.offieldthatthebackgroundisnowoutoffocus.

ChapterTwo

ChoosingaCamera

Choosingacamerawillbeeasierifyoufirstdecidewhatkindofpicturesyouwanttotake,thenthinkaboutwhichbasiccameradesignbestfitsyourneeds.Ifyourpicturetakingconsistsofoccasionalsnapshotsoffamily,friends,orsightseeingviews,thenaninexpensive,nonadjustable,point-and-shootcameramaybesatisfactory.Ifyouareaphotographystudent,aseriousamateur,orjustsomeonewhowouldliketolearnmoreaboutphotography,youwillwantanadjustablecamera.Formostpeoplethisisadigitalor35mm(thirty-fivemillimeterdescribesthefilmsize)single-lensreflexcamera.Acameramayhaveautomaticfeatures,butataminimumitshouldalsogiveyoutheoptionofmanuallyselectingthefocusingdistanceandeithertheshutterspeedoraperture,preferablyboth.Youalsowantacamerathataccepts

SINGLE-LENSREFLEXCAMERAS

interchangeablelenses.BesuretoreadaboutlensesinChapter3;lensselectionisimportantinyourchoiceofacamera.Shoparoundtocompareprices,accessories,andservice.Makesureyoulikethewaythecamerafitsinyourhands,andthatbuttonsandknobsareconvenientlyplacedandeasytomanipulate.Withthemoreautomaticmodels,seeifitisconvenienttooverridetheautomaticfeatures.Ifyouwearglasses,makesureyoucanseetheentireimage.Youmaybeabletofindagoodusedcameraataconsiderablesaving,butlookoverusedequipmentcarefully.Avoidcameraswithdents,scratchedlenses,rattles,orgougedscrewheadsthatcouldindicateahomerepairjob.Areputabledealerwillexchangeacamera,neworused,ifyourfirstphotographsareunsatisfactory.Examineyour

thatmayneedrepair.Itsmovingmirrormakesaclackduringexposure,veryloudinthemedium-formatmodels;thisisadrawbackifyouarestalkingwildanimalsorself-consciouspeople.Whenthemirrormovesupforexposure,itmomentarilyblacksouttheviewingimage,adistractioninsomesituations.Andthemotionofthemirrorandshuttermaycausevibrationsthatmakethecameradifficulttoholdsteadyatslowshutterspeeds.Choosingacamera;Single-lensreflexcamerasarethemostpopularwhenabuyermovesbeyondsnapshotlevel,

firstframesorthatfirstrollcarefullyforsoftfocus,scratches,orothersignsoftrouble.Thesizeofthefilmortheresolutionofthesensordeterminethequalityoftheimagethecameraproduces.High-qualityimagescanbeproducedby35mmfilm,whichislessthan11/2-incheswide.Buta35mmnegative,forexample,hastobeenlargedmuchmorethana4x5-inchnegativetomakethesamesizeprint.Thelargerthenegative,thesharper,smoother,andmoredetailedanyimagewillberendered.FilmsizealsodeterminesthesizeofthecameraitselfObviously,thesmallerthefilmformat,thesmallerthecameracanbe.Onemeasureofadigitalcamera'ssensoristhenumberofpixelsitcaptures.Allotherthingsbeingequal,atenmegapixel(MP)cameracanmakehigher-qualitypicturesthanasixmegapixelcamera.

Asingle-lensreflexcamerahasaviewingsystemthatisbuiltaroundamirror.Whileviewing,lightcomingthroughthecameralensisreflectedbythismirroruptoaviewingscreen,thenusuallytravelstoafive-sidedpentaprismthatturnstheinvertedimagearoundsoitappearsthecorrectwaytotheeye(diagram,belowleft).Whentheshutterisreleased,themirrorfirstswingsup,permittinglighttoreachtheshutterandfilmorsensoratthebackofthecamera(diagram,belowright).Theimageproducedisthesameastheimageviewedthroughthelens,

Asingle-lensreflex(SLR)camerashowsyouthescenedirectlythroughthelens.Thecamerahasamirrorandpentaprismthatletyouseethroughthetakinglenstofocusthesceneandcomposeitexactly,Wthsomecamerasyoucanpreviewhowmuchofthescenewillbesharp,fromforegroundobjectstoadistantbackground.MostSLRsuse35mmfilmorhaveadigitalsensor(theseareabbreviatedD-SLRorDSLR).Advantages;Sincetheviewingsystemusesthecameralensitself,itworkswellwithalllensesfromwideangletosupertelephoto;whateverthelenssees,youseeandthatiswhatwillberecorded.Thisisespeciallyusefulforclose-ups.Anexposuremeterbuiltintothecamerameasuresthelightpassingthroughthelens,withtheareabeingmetereddefinedintheviewfinder.Disadvantages;Asingle-lensreflexisheavierandlargerthanarangefindercamerathatusesthesamesizefilm,oracompactdigitalcamera(opposite,right).AnSLRisrelativelycomplex,withmorecomponents

30ICamera

SLRsofferagreatvarietyofinterchangeablelensesandaccessories,plusfeaturessuchasbuilt-inflash,Automaticfeaturesabound:automaticexposure,focus,flash,andfilmwindingareoftenstandard;somecanbefiredinrapidbursts.Somecamerasfollowyoureyemovementsintheviewfindertofocusautomaticallyinwhateverdirectionyouarelooking.Stopforamomenttothinkaboutwhatfeatureswillbereallyusefultoyoubeforeyoupayextraforsomespecialfeatureyoumightneedonlyonceinawhile,MakesurethecameraallowsyoutomanuallyoverrideautomaticfeatureswhenyouwanttomakeexposureandfocuschoicesyourselfForexample,somefilmcamerasautomaticallysettheISOspeedforyoubyreadingtheDXcodingonthefilmcassette.That'sconvenient,butit'sbesttohaveacamerawhereyoucanoverridethisfeaturewhenyouwanttoselectafilmspeeddifferentfromthenominalone,Alsoconsiderhowconvenientitistoselectoroverrideautomaticfeatures.Doesthecamerahaveeasy-to-adjust,convenientlylocatedknobsanddialsortiny,difficuit-to-accessbuttons,andhard-to-readmenus?

Whileviewing

Duringexposure

Choosingacamera:Medium-formatrangefindercamerascombinerelativelylargefilmwithacompactrangefinderdesign.Theyarelightweight,haveaquietshutterandabright,easy-to-focusviewfinderSomemodelshaveinterchangeablelenses.Theyarepopularwithprofessionalsandotherswhowantacamerathatiseasytocarryinthefield,butthatdeliversahigh-qualitynegativelargerthan35mm.Thefilmframeaboveis6x9cnninsize.

Medium-formatsingle-lensreflexcamerasarepopularwithphotographerswhowantanegativelargerthan35mmwiththeversatilityofasingle-lensreflex.Notonlyarelensesinterchangeable,butsometimesthecamera'sbackistoo;youcanexposepartofarollofblack-and-whitefilm,removetheback,andreplaceitwithoneloadedwithcolorfilmordesignedfordigitalcapture.Thesecamerasarebigger,heavier,andnoisierthan35mmsingle-lensreflexcamerasandthepriceisoftenhigher,too.Somemakea5x5cm(21/4-inchsquare)negative;othersarerectangular,suchas6x7cm(21/4X23/4in.)or6x4.5cm(21/4x15/8in.)

Medium-formatdigitalcamerasormedium-formatfilmcameraswithadigitaladapterbackhavealargesensor(thatmaybesquareorrectangular)tocaptureaveryhighlydetailedimage.Becausetheyarenotconsumeritemsproducedinhighvolumetheyareveryexpensive.Oiderdigitaladapterbacksformedium-formatSLRsneededtobetethered(connectedbyawire)toacomputerduringuse.

RANGEFINDER/VIEWFINDERCAMERASAviewfindercamerashowsyouthescenethroughasmallwindow(theviewfinder).Theviewfinderisequippedwithasimplelenssystemthatshowsanalmostbutnotquiteexactviewofwhatthepicturewillbe.Manyinexpensivepoint-and-shootcamerashaveaviewfinderplusautomaticfocus.Arangefindercamerahasaviewfinder,plusacoupledrangefinderthatletsyoufocusthecameramanuallyasyouviewthescene.Mostrangefinderandviewfindercamerasuse35mmfiim;afew,lil

Amacrolensisusefulforextremelycloseshots(left,top).Thelensletsyoufocusataverycloserangeandiscorrectedforaberrationsthatoccuratclosefocusingdistances.Thelensisoccasionallycalled,somewhatinaccurately,amicrolens.Somezoomlenseshaveamacrofeature.Theyfocuscloserthananon-macrozoombutnotascloseasafixed-focal-iengthmacrolens.Forthewidestofwide-angleviews,considerthefisheyelens.Afisheyehasaverywideangleofviewsomeevenmorethan180andexaggeratestoanextremedegreedifferencesinsizebetweenobjectsthatareneartothecameraandthosethatarefartheraway.Inherentinitsdesignisbarreldistortion,anopticalaberrationthatbendsstraightlinesintocurvesattheedgesofanimage.Fisheyelensesalsoproducegreatdepthoffield.Objectswithininchesofthelensandthoseinthefardistancewillbesharp.Itisnotalensforeveryorevenmanysituations,butitcanproducestartlingandeffectiveviews(bottomleft).Aberrationsaredeliberatelyintroducedinasoft-focuslens,alsocalledaportraitlens.Thegoalistoproduceanimagethatwilldiffuseandsoftendetailssuchasfacialwrinkles.Aperspective-controllensbringssomeview-cameraadjustmentstoothertypesofcameras.Thelensshiftsup,down,orsidewaystopreventparallellines,suchasthesidesofabuilding,fromtiltingtowardeachotherifthecameraistilted.Acatadioptricormirrorlensissimilarindesigntoareflectingtelescope.Itincorporatescurvedmirrorsaswellasglasselementswithinthelens.Theresultisalenswithaverylongfocallengthbutmodestsize,onemuchsmallerandlighterthanalensofequivalentfocallengththatusesonlyglasselements.Auniqueeffectcausedbythefrontmirroristhatout-of-focushighlightstakeonadonutshape.A"cat"lenshasafixedaperture,usuallyrathersmallf/8orf/11istypical.imagestabilizationcanbebuiltintoalens.Micromotorsadjustthepositionofspecialfloatinglenselements.Sometimesthesamelensisalsoavailableinaless-expensiveversionwithoutstabilization-

ChapterThreeI49

FocusingYourLensManualFocus

Withmanualfocus,youselectthepartofthesceneyouwanttobethesharpest.Whatisthemostimportantpartofthescenetobesharp?Whatdoyonwanttoemphasize?Whatdoyouexpectviewerstolookatfirst?Ifyouarephotograpliingaperson,focusontheeye.Ifthepersonisatanangleandyouareupclose,botheyesmaynotbesharpinthephotograph.Dependingonthescene,itmaybemoreimportanttohavetheneareyeorthefareyesharp.Theneareryouare,themoreimportantitistofocuscritically.Ifyouare2feetaway,focusiscritical,becausedepthoffieldwillbeshallow,withonlyanarrowareafromneartofarappearingsharp.Ifyoufocusonsomething200feetaway,everythingatthatdistanceandbeyondwillbesharp.Focusmanuallylikeyoumighttuneaguitar.Goalittlepastthepointyouthinkiscorrect,thencomeback.Ifyouadjustthefocusuntiltheimagelookssharp,thenadjustitalittlemoreuntilthesubjectlooksunsharp,thengobacktosharp,you'llknowexactlywhenyoursubjectisatitssharpest.

Sharpfocusattractstheeye.Whenyouarephotographing,itisnaturaltofocusyoureyesandthecameraonthemostimportantareaofascene.

50ILens

Followfocusisatechniquethatletsyoukeepasubjectthatismovingtowardyouwellfocused.Ifarunneriscomingtowardyou,youhavetoadjustthefocusataboutthesameratethattherunner'sdistanceischanging.Onewaytolearnhowtofollowfocusistopracticefocusingonpeoplemovingtowardandawayfromyou.Thenpracticeonfasterthings,suchasthelicenseplatesofmovingcars.Youdon'tneedthisskillifstilllifesareyouronlysubject,butitisvitalifyouwanttophotographfootballgames,autoraces,dancers,oranythingelsethatmovesfast.NOTE:Don'tforgetthatshutterspeedandaperturealsoplayanimportantroleinmakingobjectsappearsharpinthefinalpicture.Ifyourshutterspeedisn'tfastenough,amovingobjectwillappearblurredinaphotograph,nomatterhowsharplyfocuseditwas.Thisappliestoautofocusaswell.Ifyourapertureisn'tsmallenough,youmayhavefocusedonanimportantarea,butanequallyimportantnearbyareamaybeoutoffocus.See,forexample,thephotographsonpages26-27.

Sharpfocusisasignaltopayattentiontoaparticularpartofanimage,especiallyifotherpartsarenotsharp.

VIEWFINDERSCREENSFORMANUALFOCUSSingle-lensreflexandviewcamerasuseground-glassviewingscreens.Lightcomingthroughthelenshitsapaneofglassthatisetched,orground,tobetranslucent.Thisgroundglasscreatesasurfaceonwhicliaviewer,lookingatitfromtheotherside,canseeanimageandfocusit.Asyoumoveyourlensinandouttofocususuallybyrotatingittheground-glassscreenshowsclearlywhenasceneissharpandinfocus(left,above)andwhenitisnot(left).

Reflexcamerasmayalsoincludeamicroprism,acirclethatappearsdotteduntilitisfocused,andsometimesasplit-imagefocusingaidthatappearsoffsetuntiltheimageisfocused,

Rangefindercamerashavesplit-imagefocusing,whichoperatesbysuperimposingtwoimagesofthesamesubjectonthefocusingscreen(left).OneimagepassesthroughaviewfinderandoneIsreflectedbyarotatingprismconnectedtothelens.Thetwoimagesappearexactlysuperimposed(left,below)onlywhenthelensfocusessharplyonthesubject.Theredcirclesontheimagesherecallattentiontothefocusingaid.Theywouldnotappearintheviewfinder.

NOTE;Ifyouhavevisionproblems,youmightfindmanualfocusingdifficultattimes.Somecamerascomewithaviewfinderadjustmentthatallowsyoutodialinacorrection(calledadiopter)likeprescriptionglasses.Othercamerasofferanaccessorycalledadiopteriens,availableinseveralstrengths,thatscrewsdirectlyontotheeyepiecetodothesame.Youroptometristcantellyoutheappropriatecorrectiontobuy

ELUOTTERWinNewYork,1946Witheverythinginthephotosoftexceptthedogandfeet,whichareinthesameplaneoffocus,thephotographerleavesnodoubiaboutwherehewantstheviewer'seyetogo.Thehumanbrainlooksforsharpnessinasceneorinaphotograph.Bycontrollingfocus,photographersalsocancontrolwherepeoplelookwhenanimageisviewed.

ChapterThree|51FocusingYourLenscontinuedAutomaticFocus

Automaticfocus(AF)doesthefocusingforyou.Inthesimplestdesigns,youpresstheshutter-releasebuttonandthelensbringstheimageintofocus.Thecameraadjuststhelenstofocussharplyonwhateverobjectisatthecenteroftheviewfinderorwithinthefocusingbrackets.Thistypeofautofocusworkswellinsituationswherethemainsubjectisandstaysinthemiddleofthepicture.Thecameramaybeepordisplayaconfirmationlightwhenithasfocused,butthepresenceofalightdoesnotassurethatthepicturewillbesharpoverall.Ifyoursubjectisnotinthecenter,youcanuseautofocuslocktomakeitsharp.Framethesubjectwithinthefocusingbracketsorsimplypointthecamerastraightatit.Totemporarilylockinthefocus,presstheshutterreleasehalfwaydown.Keepingtheshutterbuttonpartiallypressed,reframethescene,thenpresstheshutterreleaseallthewaydownforanexposure(seephotos,right).Wide-areafocussystemsprovidemoreoptions.Someviewfindersdisplayseveralfocusingbrackets.Byrotatingadialorthumbwheelonthecameraback,youselectabracketthatcoversthesubjectyouwanttobesharp.Whenyoupresstheshutter,thecamerafocusesontheselectedareaallowingyoutomaintainyourframingwithouthavingtocenter,lock,andreframeeachpicture.Thisallowsyoutoshootfast-movingsubjectsthatarenotinthecenteroftheframe(seephoto,oppositepage,belowright).Somewide-areaautofocussystemsuselightreflectedoffyoureyetoidentifyyoursubjectbythedirectionyouarelooking,andthereforewhatareaofthepicturetobringintosharpfocus.Othersystemsautomaticallyselectthenearestsubjectinthepictureandfocusthere.Onceyoulockontoasubject,somecameraspredictwherethesubjectislikelytobenext,keepingthesubjectinfocusevenifitmovesacrosstheframe.Thesetrackingsystemscanlockontoasubject,

52ILens

adjustingthefocusasthesubjectmovescloserto,orfartherfrom,thecamera.Thesesystemsworkespeciallywellifthesubject,likearacecar,istravelingataconstantspeedtowardorawayfromthecamera.Somecamerashavetwoautofocussystems.Activeautofocussendsoutabeamofinfraredwaves.Thecamerausesthepartofthebeamthatbouncesbacktomeasurethedistancetothesubject.Passiveautofocuslooksinsteadattheimageinsidethecamera,usingtheprinciplethatcontrastonthefocalplaneisgreatestwhenthesubjectissharpest.Bothareusedbecauseneitheroneworksineverysituation.Theinfraredbeaminactiveautofocus,forexample,willbouncebackfromtheglassinawindowinsteadoffromasubjectontheothersideoftheglass.Passiveautofocusmaymissthefocusifasubjecthasverylowcontrast,isinverydimlight,orconsistsofarepetitivepatternlikewindowblindsorplaid.Camerasthatemploybothsystemsaremorelikelytofindmaximumsharpnessundermostconditions.Anautofocussystemcanbefooled.Ifyouarephotographingasoccergamefocusingonthegoalie,forexample,andtherefereemovesinfrontofyourcamera,autofocusmaytracktherefereeandnottheplayer.Thecameradoesnotknowwhatyouaretryingtophotograph,sounwantedsubjectscancausethelenstofocusincorrectly.Yourcameramayletyouselectamongitsseveralfocusmodes.Manualfocusisfrequentlysupplementedbytwootheroptionssingle-shotautofocus,sometimescalledfocuspriority,andcontinuousfocus.Withamoderncamera,ifyouwantthemachinetomakequickandaccuratedecisionsforyou,youmustunderstanditsmethods.Readyourcamera'sinstructionssoyouknowhowitsautofocusmechanismoperatesandwhenyouwouldbebetterofffocusingmanually.

CENTER-WEIGHTEDAUTOFOCUSLOCK

Shutter-releasebuttonSubjectofftenter,outoffocus.Autofocuscamerasoftenfocusonthecenterofascene,Thiscanmakeanoff-centermainsubjectoutoffocusifitisatadifferentdistancefromwfiateverisatthecenterAbove,bracl