Duk Abubuwan da kuka taɓa so ku sani game da DOF (Zurfin Filin)

Lokacin da na sanya makon da ya gabata na nuna hotunan yadda ake sanya idanu cikin hankali, na sami kyakkyawar sharhi daga ɗayan masu karatu na. Ya yarda ya rubuta muku duka a Zurfin Filin wanda ya kasance mafi kyawun fasaha wanda hanyata ta gani take bayani. Na gode Brendan Byrne don wannan bayanin mai ban mamaki.

Tsarin aikin manhajar kwamfuta ta tsakiya

Jodi ya kasance mai kirki ya roƙe ni in rubuta wordsan kalmomi game da DOF ko zurfin filin. Ina fatan gabatar da wannan bayanin ta hanya mai sauƙin fahimta ba tare da neman ilimin lissafi ba ko kuma komawa ga babin ilimin kimiyyar gani a cikin kimiyyar lissafi na kwaleji. Akwai bayanai da yawa akan Intanet game da DOF, Zan sanya wasu hanyoyin haɗi zuwa shafuka masu ban sha'awa.

Da fatan za a tuna, ni ba ƙwararren mai ɗaukar hoto bane, masanin kimiyyar lissafi, ko lissafi, don haka na rubuta abin da na yi imanin daidai ne, dangane da ɗaukar hoto mai son shekaru 25. Idan kowa yana da wata tsokaci, tambaya, ko suka, don Allah imel na. A nan ba komai:

Sau da yawa nakan kalli hotuna na da aka watsar don gano yadda na sata su. Idan matsalar ta shafi batun rashin kaifin hankali, yawanci zai zama ɗayan matsaloli guda huɗu. A cikin wannan labarin za mu mai da hankali kan abin ƙarshe.

1. Girgiza kamara - Shan Starbucks da yawa a safiyar ranar harbi & hannayen tsufa wasu lokuta kan sa kyamara ta ta girgiza yayin fallasar. Ana iya ganin wannan sau da yawa yayin bayanawa mafi tsayi. Thea'idar babban yatsan yatsa ita ce bayyanar da hannu zai kasance yana da saurin rufewa fiye da nesa 1 / nesa. Misali, akan ruwan tabarau na na 55mm, ya fi kyau in yi harbi da saurin rufewa sama da 1/60 na dakika. Hanyoyi masu yuwuwa: Amfani da ruwan tabarau na IS (karfafa hoto), ta amfani da saurin rufe sauri, ko amfani da hanya mai mahimmanci zai taimaka wajen hana al'amuran girgiza kyamara.

1. Matsayin motsi - Wannan na iya zama da wahala a iya sarrafa shi, musamman a yayin fallasawa da yawa. Hanyoyi masu yiwuwa: Amfani da saurin rufe sauri. Tunda za a sami ɗan lokaci kaɗan don batun ya motsa, za a kuma sami damar rashin haske. Amfani da walƙiya yana iya taimakawa daskare motsi. Kuma tabbas, koyaushe zaka iya gaya wa batun ya ci gaba (Sa'a da wancan.)

1. Gilashin tabarau mara kyau. - Sau da yawa na taɓa jin cewa idan ya zama dole ku zaɓi tsakanin biyun, zai fi kyau ku saka hannun jari a cikin gilashi mai kyau maimakon cikin jikin kyamara. Duk da yake Ina so in sami ruwan tabarau na aji na Canon, na yi ƙoƙari in sayi ruwan tabarau mai kyau yadda zan iya iyawa.

1. DOF - Zurfin filin shine yanki kusa da ma'anar da ke cikin hankali. A ka'idar, ainihin mayar da hankali abu ne mai yiwuwa a cikin maki guda daya daga ruwan tabarau. Ana iya lissafin wannan ma'anar ta hanyar lissafi bisa larura da dama. Abin farin ciki, a gare mu mutane, idanunmu ba su cika damuwa ba, don haka a maimakon haka, akwai kewayon yanki a gaba da bayan wancan mahimmin abin da ake ɗauka mai karɓa. Bari mu duba wannan kusa.

Da fatan za a tuna cewa girman yankin da aka yarda da shi ba abu bane mai kyau ko mara kyau. A takaice dai, babban DOF ba lallai bane ya zama abu mai kyau. Duk ya dogara da abin da kuke nema. Masu ɗaukar hoto za suyi amfani da DOF don fa'idodin su kuma ana iya sarrafa shi saboda dalilai na fasaha.

Misali, hotunan hoto yakan yi amfani da DOF mai zurfin zurfi don sanya hankali kan batun yayin dusashe sauran harbi.

A cikin hotunan shimfidar wuri, a gefe guda, mai ɗaukar hoto na iya son hoton ya sami babban DOF. Wannan zai ba da damar babban yanki ya kasance a cikin hankali, daga gaba zuwa bango.

Af, na karanta wani wuri, cewa mutane ana ɗora su a hoto zuwa withanƙanin haske DOF, saboda yayi kama da yadda idanun mu suke ganin abubuwa. Idanunmu suna aiki sosai kamar ruwan tabarau na kyamara. Tare da hangen nesan mu, ba zamu ga abubuwa a sarari daga kusan zuwa rashin iyaka a cikin wani kallo guda ba, amma maimakon haka idanun mu sukan daidaita don mayar da hankali kan jeri daban-daban na nesa.

Hoto na farko misali ne tare da DOF mara zurfin zurfin gaske. Na harba wadannan tulips din daga kusan kafa 3 nesa a 40mm f / 2.8 a 1/160 na biyu. Kuna iya ganin tulip na gaba yana mai da hankali (ƙari ko lessasa), yayin da a bango, galibi, tulip na baya ya dushe. Don haka duk da cewa tulip na baya inci 4 ko 5 ne kawai daga tulip na gaba, tulip na baya baya daga kewayon karɓaɓɓu na mayar da hankali.

Hoton dandalin Roman misali ne na DOF mafi zurfin zurfi. An harbe shi daga kimanin ƙafa 500 daga 33mm f / 18 a 1/160 na biyu. A cikin wannan harbi, abubuwa suna cikin mayar da hankali daga gaba zuwa bango.

Me yasa waɗannan karɓaɓɓun jeri waɗanda aka yarda dasu suka faru kamar yadda sukayi a waɗannan hotunan? Zamu bincika abubuwan da suka shafi DOF a waɗannan hotunan.

Abubuwa da yawa sun shafi DOF. Yanzu, Ba zan ba ku tsarin da za ku lissafa DOF ba saboda zai sa wannan labarin ya zama mai rikitarwa. Idan kowa yana sha'awar dabarun, da fatan za a yi min imel zan iya aiko muku da su. Af, akwai babban gidan yanar gizo inda zaka iya lissafin abin da aka ba DOF. http://www.dofmaster.com/dofjs.html

Don haka maimakon kallon lissafi a bayan sa, zan maida hankali kan abubuwan da ke haifar da DOF ya canza kuma in nuna muku yadda zaku iya canza sarrafa DOF ɗin ku.

Akwai manyan abubuwa guda huɗu waɗanda suka shafi girman kewayon yankin da aka yarda dashi: Su ne:

• Length Focal - Tsarin mai da hankali kan ruwan tabarau. Watau, yadda aka zuƙo cikin batun kai kake, misali, 20mm akan ruwan tabarau na 17-55mm.
• Nisa zuwa Jigon - Yaya nisan batun da kake so ka maida hankali akai.
• Girman budewa - (f / tasha) (Girman buɗe ƙofa) - Misali, f / 2.8
• Da'irar rikicewa - yana rayuwa har zuwa sunansa saboda yana da matukar rikitarwa & rikice-rikice wanda ya bambanta akan duk kyamarori. A saman gidan yanar gizon da aka ambata zaka iya zaɓar kyamararka, kuma zai shiga madaidaiciyar da'irar rikicewa. Ba za mu kalli wannan ba saboda ba za ku iya canza shi ba sai dai idan kuna amfani da kyamarar ta daban.

Don haka, zamu mai da hankali kan ukun farko, saboda waɗannan abubuwa galibi suna cikin ikonmu.

Tsayin mai da hankali - Wannan shine yadda aka zuƙo cikin batun da kuke. Wannan ya shafi DOF sosai. Yana aiki kamar haka, gwargwadon yadda aka zuƙo maka, da zurfin zurfin DOF ɗinka. Misali, idan batun ka yana da ƙafa 20, kuma ka yi amfani da tabarau mai kusurwa kamar 28mm, yankin da ke wurin da aka yarda da shi ya fi girma idan ka yi amfani da ruwan tabarau na zuƙowa a 135mm. Amfani da gidan yanar gizon da aka ambata a sama, don wannan misali, a 28mm, madaidaiciyar kewayon mayar da hankali tana gudana daga ƙafa 14 zuwa ƙafa 34, yayin da idan na zuƙo zuwa 135mm, madaidaiciyar hanyar mayar da hankali tana gudana daga ƙafa 19.7 zuwa ƙafa 20.4. Duk waɗannan misalan, suna f / 2.8 akan Canon 40D na. A 28mm, jimlar karɓaɓɓiyar kewayon kusan ƙafa 20 ne, alhali kuwa a 135mm, zangon da aka yarda da shi bai kai ƙafa 1 ba. Abu ne mai sauki don samun damar daidai a fadi mai nisa na 28mm fiye da wanda aka zuƙo shi tsawon 135mm.

Nisa zuwa Jigon - Wannan shine yadda ruwan tabarau yake kusa da batun da kuke so ku mai da hankali. DOF tana aiki kamar haka idan yazo da nisa zuwa batun. Kusancin da kuke kusa da batun, mafi zurfin zurfin DOF zai kasance. Misali, akan 40D dina a f / 2.8 ta amfani da ruwan tabarau na 55mm, idan batun yana da ƙafa 10, zangon da ake karɓa yana zuwa daga ƙafa 9.5 zuwa ƙafa 10.6. Idan batun yakai ƙafa 100 daga nesa, zangon da ake karɓa daga ƙafa 65 zuwa 218. Wannan babban bambanci ne, a ƙafa 10; Yankin yankin da aka mai da hankali kusan kafa 1 ne, alhali kuwa a ƙafa 100, zangon da aka mai da hankali ya wuce ƙafa 150. Har yanzu, mayar da hankali ya fi sauƙi, lokacin da batun ku ya yi nisa.

Girman budewa - Abu na ƙarshe a cikin ikon mu shine girman buɗewa ko f-stop. Don sanya lamura su zama masu rikitarwa, karamin f-stop size (kamar f / 1.4) yana nufin buɗewar ku a buɗe take, kuma babban lambar f-stop (kamar f / 16) yana nufin buɗewar ku ta yi kadan. Hanyar buɗewa ta shafi DOF shine kamar haka. Numberaramin lambar f-stop (wanda ke nufin ana buɗe buɗewa sosai) yana da zurfin DOF fiye da babban lambar f-tsayawa (inda buɗe ido karami ne). Misali, akan babban ruwan tabarau na zuƙowa da aka saita a 300mm, idan an saita f-stop zuwa 2.8, kuma ina harbi a kan batun ƙafa 100 daga nesa, zangon da aka yarda zai fara daga ƙafa 98 zuwa ƙafa 102, amma idan na yi amfani da karamin f-stop na 16, to, kyakkyawar kewayon daga 91 zuwa ƙafa 111. Don haka, tare da ruwan tabarau a buɗe, keɓaɓɓiyar kewayon kusan ƙafa 4 ne, amma tare da ƙaramar buɗewa (babban f-stop), kyakkyawan zangon yana da ƙafa 20. Bugu da ƙari, mayar da hankali ya fi sauƙi, lokacin da f-tsayawa babba (buɗewa karami ce).

Yanzu mun sake nazarin manyan abubuwan guda uku da suka shafi DOF, bari mu kalli misalai na na hoto na biyu da suka gabata, kuma bari mu ga dalilin da yasa na sami sakamakon da nayi.

A hoto na farko tare da tulips, manyan abubuwa guda uku a cikin harbi sune: Hoto hoto a 40mm, batun a ƙafa 3, ta amfani da buɗe f / 2.8. Amfani da kalkuleta, zangon yanki mai karɓa mai sauƙi yana gudana daga ƙafa 2.9 zuwa 3.08. Wannan duka kewayon ƙafa 18 ko kusan inci 2. Nisa daga gaba zuwa bayan tulips yakai inci 4 ko 5, saboda haka tulip din baya daga kewayon da ake karba saboda haka, yana da matukar birgima.

A hoto na biyu a cikin Rome, manyan abubuwan guda uku sune: Hoton hoto a 33mm, batun kusan ƙafa 500, ta amfani da buɗe f / 18. Amfani da kalkuleta, karɓaɓɓen kewayon da aka zahiri yana gudana daga ƙafa 10.3 zuwa Infinity. Wannan shine dalilin da ya sa, duk hoton yana cikin hankali. Don haka koda wata yana cikin hoto na, zai zama mai kaifi ma.

Don haka menene wannan duka yake nufi a gare ku? Shin kawai za mu harbi batutuwa masu nisa tare da manyan tabarau masu kusurwa a manyan wuraren tsayawa? Babu shakka ba, muna so mu iya tsara hotuna ta amfani da DOF ta hanyar da ta fi dacewa don yanayin da muke ƙoƙari. Ya kamata mu tuna da abin da ya shafi DOF, kuma mu koyi yadda za mu yi amfani da shi don cimma burinmu.

Don taƙaita:

Lokacin da Nisa zuwa Jigon Ya (ara (batun yana kara nisa), DOF yana ƙaruwa

Lokacin da Tsawon ocari ya Increara (lokacin da muka zuƙowa ciki), DOF yana raguwa

Lokacin da Girman buɗewa ya (ara (lambar dakatarwa ta zama karami), DOF yana raguwa

Sa'a mai kyau & Farin ciki mai kyau!

Brendan Byrne

Mai Girma: http://www.flickr.com/photos/byrnephotos/

email: [email kariya]

Shafuka masu amfani:

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

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

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