Konke oke wafuna ukwazi nge-DOF (ubunzulu bentsimi)

Xa ndathumela kwiveki ephelileyo ndibonisa iifoto zendlela yokujonga amehlo, ndafumana ingxelo emnandi evela komnye wabafundi bam. Uvumile ukuba anibhalele iposti nonke ngobunzulu bentsimi eyayiyi-tad ethe kratya kwezobuchwephesha kwindlela yam ebonakalayo yokuchaza. Ndiyabulela uBrendan Byrne ngale ngcaciso imangalisayo.

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UJodi wayenobubele ngokwaneleyo ukuba andibuze ukuba ndibhale amagama ambalwa malunga ne-DOF okanye ubunzulu bentsimi. Ndiyathemba ukuveza olu lwazi ngendlela ekulula ukuyiqonda ngaphandle kokubhenela kwimathematics ephambeneyo okanye ubuyele kwisahluko malunga nokukhanya kwincwadi yam yeekholeji yeekholeji. Kukho ulwazi oluninzi kwi-Intanethi malunga ne-DOF, ndiza kuthumela amakhonkco kwiindawo ezinomdla.

Nceda ugcine engqondweni, andinguye umfoti oqeqeshiweyo, ifiziksi, okanye isazi sezibalo, ke ndibhale into endikholelwa ukuba ichanekile, isekwe kwiminyaka engama-25 yokufota. Ukuba nabani na unamagqabaza, imibuzo, okanye ukugxekwa, nceda undithumelele imeyile. Nantsi ayiyonto:

Ndihlala ndijonga kwiifoto zam ezilahliweyo ukuze ndibone ukuba ndizisonge njani. Ukuba ingxaki ibandakanyekile kwisifundo ingabi bukhali ngokwaneleyo, iya kuba yenye yeengxaki ezine. Kule nqaku siza kugxila kwinto yokugqibela.

1. Ikhamera inyikima -Ukusela kakhulu i-Starbucks ngentsasa yokudubula kunye nezandla ezigugileyo ngamanye amaxesha kubangela ukuba ikhamera yam ishukume ngexesha lokuvezwa. Oku kunokubonwa rhoqo ngexesha lokuveza ixesha elide. Umgaqo ombi wesithupha kukuba ukugcinwa kwesandla kufuneka kube nesantya se-shutter ngokukhawuleza kune-1 / kumgama wokugxila. Umzekelo, kwiilensi zam ezingama-55mm, kungcono ndibhence ngesantya se-shutter ngokukhawuleza kune-1/60 yomzuzwana. Izisombululo ezinokubakho: Sebenzisa i-IS (ukuzinzisa umfanekiso) iilensi, usebenzisa isantya se-shutter ngokukhawuleza, okanye ukusebenzisa i-tripod kuya kunceda ukuthintela imicimbi yokugungqa kwekhamera.

1. Ukuhambisa isifundo -Oku kunokuba nzima ukulawula, ngakumbi ngexesha lokuveza ixesha elide. Izisombululo ezinokubakho: Sebenzisa isantya se-shutter esikhawulezayo. Kuba kuya kubakho ixesha elincinci lokuhamba kwesifundo, kuya kubakho ukubanethuba elincinci lokufiphala. Ukusebenzisa ifleshi kunokunceda ekubambeni ukuhamba. Kwaye ke, unokuhlala uxelela umxholo ukuba uhlale uzolile (Ngethamsanqa naloo nto.)

1. Iilensi ezikumgangatho ophantsi. - Ndihlala ndisiva ukuba kufuneka ukhethe phakathi kwezi zimbini, kungcono ukuba utyale imali kwiglasi esemgangathweni elungileyo kunakwikhamera yomzimba. Ngelixa ndingathanda ukuba nelensi yeklasi eyi-L ye-Canon yam, ndiyazama ukuthenga ilensi entle njengoko ndinako ukufikelela kuyo.

1. DOF -Ubunzulu bentsimi yindawo ejikeleze inqaku ekugxilwe kulo. Kwithiyori, ukugxila ngqo kunokwenzeka kwinqanaba elinye kuphela kwilensi. Eli nqaku linokubalwa ngokwezibalo ngokusekwe kwinani lezinto. Ngethamsanqa, kuthi bantu, amehlo ethu awanangxaki, ke endaweni yoko, kukho uluhlu lwendawo ngaphambili nangasemva kwale ndawo kugxilwe kuyo ethathelwa ingqalelo eyamkelekileyo. Masiqwalasele oku kufutshane.

Nceda ugcine engqondweni ukuba ubungakanani bendawo ekugxilwe kuyo ayisiyonto intle okanye embi. Ngamanye amagama, i-DOF enkulu ayisiyonto intle. Konke kuxhomekeke kwinto oyikhangelayo. Abafoti baya kusebenzisa i-DOF ukuze ibancede kwaye inokusetyenziselwa izizathu zobugcisa.

Umzekelo, iifoto zomzobo zihlala zisebenzisa i-DOF engacacanga kakhulu ukubeka ingqalelo kwisifundo ngelixa iphazamisa yonke enye into.

Kwindawo yokudubula komhlaba, kwelinye icala, umfoti angafuna ukuba ifoto ibe ne-DOF enkulu. Oku kuyakuvumela indawo enkulu ukuba ijolise, ukusuka ngaphambili ukuya ngasemva.

Ngendlela, ndikhe ndafunda ndaweni ithile, ukuba abantu batsaleleke ngokwemvelo kwiifoto nge-DOF engekho nzulu, kuba iyafana kakhulu nendlela amehlo ethu azibona ngayo izinto. Amehlo ethu asebenza kakhulu njengelensi yekhamera. Ngombono wethu, asiziboni izinto ngokucacileyo ukusuka kufutshane ukuya kufikelela kubunzulu ngamehlo, kodwa endaweni yoko amehlo ethu alungelelanisa ukugxila kumanqanaba ohlukeneyo omgama.

Ifoto yokuqala ngumzekelo nge-DOF engekho nzulu. Ndizidubule ezi tulips zivela malunga neenyawo ezintathu ukusuka kwi-3mm f / 40 nge-2.8/1 yesibini. Ungayibona itulip yangaphambili ijolise (ngaphezulu okanye ngaphantsi), ngelixa ngasemva, ikakhulu, ngasemva i-tulip ifiphele. Ke ngaphandle kwenyani yokuba i-tulip yangasemva zii-intshi ezi-4 okanye ezi-5 kuphela ukusuka kwitulip yangaphambili, itulip yangemva iphuma kuluhlu olwamkelekileyo lokugxila.

Ifoto yeforum yaseRoma ngumzekelo we-DOF enzulu ngakumbi. Yadutyulwa ukusuka kwi-500 yeenyawo ukusuka kwi-33mm f / 18 nge-1/160 yesibini. Kula mfanekiso, izinto zijolise ngaphambili ukusuka ngasemva ukuya ngasemva.

Kutheni le nto ezi ndawo zamkelekileyo kugxilwe kuzo zenzeke ngendlela ezenze ngayo kwezi foto? Siza kuvavanya izinto ezichaphazele i-DOF kule mifanekiso.

I-DOF ichaphazeleka zizinto ezininzi. Ngoku, andizukukunika ifomula yokubala i-DOF kuba izakwenza eli nqaku libe nzima ngokungeyomfuneko. Ukuba nabani na unomdla kwiifomula, nceda undithumelele imeyile kwaye ndingabathumela zona. Ngendlela, kukho iwebhusayithi enkulu apho unokubala ukuba yintoni i-DOF enikiweyo. http://www.dofmaster.com/dofjs.html

Ke endaweni yokujonga izibalo ezisemva kwayo yonke, ndiza kugxila kwizinto ezibangela ukuba i-DOF itshintshe kwaye ikubonise ukuba ungayitshintsha njani i-DOF yakho.

Zine izinto eziphambili ezichaphazela ubungakanani boluhlu lwendawo eyamkelweyo ekugxilwe kuyo: Bazi:

• Ubude obude Useto olugxile kwiilensi zakho. Ngamanye amagama, usondeze kangakanani kwisifundo okuso, umzekelo, i-20mm kwilensi eyi-17-55mm.
• Umgama kwiSifundo - Kukude kangakanani kwisifundo ofuna ukugxila kuso.
• Ubungakanani bendawo - (f / yeka) (Ubungakanani bokuvula i-shutter) - Umzekelo, f / 2.8
• Isangqa sokudideka -Uphila ngokuhambelana negama layo kuba yinto enzima kakhulu kwaye iyabhidisa eyahlukileyo kuzo zonke iikhamera. Kule webhusayithi ikhankanywe apha ngasentla unokukhetha ikhamera yakho, kwaye iya kungena kwisangqa esifanelekileyo sokudideka. Asizukuyijonga le nto kuba ngekhe uyitshintshe ngaphandle kokuba usebenzisa ikhamera eyahlukileyo.

Ke, siza kugxila kwezintathu zokuqala, kuba ezi zinto zihlala ziphantsi kolawulo lwethu.

Ubude obujolisiweyo -Uyile ndlela yokusondeza kumxholo okuwo. I-DOF ichaphazeleka kakhulu koku. Isebenza ngolu hlobo lulandelayo, kokukhona usondeza, i-DOF yakho iya kuba mbi. Umzekelo, ukuba isifundo sakho siziinyawo ezingama-20, kwaye usebenzisa iilensi ezibanzi ezinama-angled njenge-28mm, indawo kwindawo eyamkelekileyo ekugxilwe kuyo inkulu kakhulu kunokuba usebenzisa i-lens zoom kwi-135mm. Sebenzisa le webhusayithi ikhankanywe apha ngasentla, kulo mzekelo, kwi-28mm, uluhlu olwamkelekileyo lokugxila luqala ukusuka kwi-14 iinyawo ukuya kwi-34 yeenyawo, ngelixa ukuba ndisondeza ukuya kwi-135mm, uluhlu olwamkelekileyo lokugxila luqala kwi-19.7 yeenyawo ukuya kwi-20.4 yeenyawo. Yomibini le mizekelo ikwi-f / 2.8 kwi-Canon 40D yam. Ku-28mm, uluhlu olujolise ngokwamkelekileyo lumalunga neenyawo ezingama-20, ngelixa i-135mm, uluhlu olwamkelekileyo lungaphantsi kwe-1 leenyawo. Kulula ngakumbi ukugxila ngqo kububanzi obugxile kububanzi be-28mm kunakwindawo esondeleyo kubude be-135mm.

Umgama kwiSifundo -Nantsi indlela ekukufutshane ngayo ilensi yakho kwisifundo ofuna ukugxila kuso. I-DOF isebenza ngolu hlobo lulandelayo xa kufikwa kumgama kumxholo. Ukusondela kwakho kwesi sifundo kuya kuncipha kwi-DOF. Umzekelo, kwi-40D yam ngo-f / 2.8 usebenzisa iilensi ezingama-55mm, ukuba isifundo siziimitha ezili-10 kude, uluhlu olwamkelekileyo luhamba ukusuka kwi-9.5 yeenyawo ukuya kwi-10.6 yeenyawo. Ukuba isifundo siziimitha ezili-100 kude, uluhlu olwamkelekileyo luvela kwi-65 ukuya kwi-218 yeenyawo. Lo ngumahluko omkhulu, kwii-10 iinyawo; Uluhlu lwendawo ekugxilwe kuyo lumalunga neenyawo enye, ngelixa i-1 yeenyawo, uluhlu olugxilwe ngaphezulu kwe-100 yeenyawo Kwakhona, ukugxila kulula, xa isifundo sakho sikude.

Ubungakanani bendawo -Into yokugqibela kulawulo lwethu bubungakanani be-aperture okanye i-f-stop. Ukwenza imicimbi ingabhidisi ngakumbi, ubungakanani obuncinci bokumisa (njenge f / 1.4) kuthetha ukuba ukuvula kwakho kuvuleke ngokubanzi, kwaye nenombolo enkulu ye-f-stop (njenge f / 16) kuthetha ukuba ukuvula kwakho kuncinci kakhulu. Indlela echaphazeleka ngayo i-DOF kukuvula kungoku kulandelayo. Inani elincinci le-f-stop (okuthetha ukuba ukuvula kuvulwe ngokubanzi) ine-DOF engekho nzulu kunenombolo enkulu yokumisa f (apho indawo encinci incinci). Umzekelo, kwilensi yam enkulu yokusondeza ebekwe ku-300mm, ukuba i-f-stop isetelwe ku-2.8, kwaye ndiyadubula kwisifundo esikwiimitha ezili-100, uluhlu olwamkelekileyo luhamba ukusuka kwi-98 yeenyawo ukuya kwi-102 yeenyawo, kodwa ukuba ndisebenzisa f-stop encinci ye-16, emva koko uluhlu oluhle luhamba ukusuka kuma-91 ukuya kuma-111. Ke, xa iilensi ivulekile ngokubanzi, indawo ekugxilwe kuyo eyamkelekileyo imalunga neenyawo ezi-4, kodwa nge-aperture encinci (enkulu f-stop), uluhlu oluhle lumalunga neenyawo ezingama-20. Kwakhona, ukugxila kulula, xa i-f-stop inkulu (ukuvula incinci).

Ngoku ekubeni sihlolisise izinto ezintathu eziphambili ezichaphazela i-DOF, masiqwalasele imizekelo yam emibini yemifanekiso yangaphambili, kwaye masibone ukuba kutheni ndifumana iziphumo endizenzileyo.

Kwifoto yokuqala kunye nee-tulips, izinto ezintathu eziphambili kwifoto yayi: Ifoto ifotwe kwi-40mm, ixhomekeke kwi-3 yeenyawo, isebenzisa f / 2.8 ukuvula. Usebenzisa ikhalityhuleyitha, uluhlu lwendawo egxile ngokwamkelekileyo libaleka ukusuka kwi-2.9 ukuya kwii-3.08 iinyawo. Olu luhlu olupheleleyo lwee-.18 zeenyawo okanye malunga nee-intshi ezimbini. Umgama ukusuka ngaphambili ukuya kwii-tulips zangasemva wawumalunga nee-intshi ezi-4 okanye ezi-5, ke ngoko i-tulip yangemva iphuma kuluhlu olwamkelekileyo kwaye ke, ifiphele kakhulu.

Kwifoto yesibini eRoma, ezi zinto zintathu ziphambili yayi: Ifoto ifotwe kwi-33mm, ixhomekeke kwi-500 yeenyawo, isebenzisa f / 18 ukuvula. Sebenzisa ikhalityhuleyitha, uluhlu olwamkelekileyo olujolise ngokwenyani lubaleka ukusuka kwi-10.3 yeenyawo ukuya kwi-Infinity. Kungenxa yoko le nto, ifoto iphela ijolise kakhulu. Ke nokuba inyanga ibisefotweni yam, ibiya kuba bukhali nayo.

Ke oku kuthetha ntoni kuwe? Ngaba kufuneka sidubule kuphela izifundo ezikude ngeelensi ezibanzi ezi-engile kwiindawo ezinkulu zokuma? Ngokucacileyo akunjalo, sifuna ukubanakho ukuqamba iifoto sisebenzisa i-DOF ngendlela esebenza ngokukuko kwinkangeleko esizama ukuyenza. Kuya kufuneka sigcine engqondweni into echaphazela i-DOF, kwaye sifunde indlela efanelekileyo yokuyisebenzisa ukufezekisa iinjongo zethu.

Shwa nkathela:

Xa umgama wokunyuka kwezifundo (isifundo siya kude), i-DOF iyanda

Xa ubude boJoliso busonyuka (xa sisondeza), i-DOF iyancipha

Xa Ubungakanani Bokunyuka Kwenyuka (inombolo yokumisa f iyancipha), i-DOF iyancipha

Ngethamsanqa & ngokudubula Happy!

UBrendan Byrne

Flickr: http://www.flickr.com/photos/byrnephotos/

email: [imeyile ikhuselwe]

Iindawo eziluncedo:

http://www.dofmaster.com/dofjs.html

http://www.johnhendry.com/gadget/dof.php

http://en.wikipedia.org/wiki/Depth_of_field