F-Stop lossis Focal Ratio: Nws Yog Dab Tsi Thiab Vim Li Cas Nws Tseem Ceeb
F-nres or focal ratio (qee zaus hu ua f-ratio lossis txheeb ze pauj) yog ib lo lus siv hauv kev yees duab thiab hais txog qhov sib piv ntawm qhov focal ntev ntawm lub lens thiab txoj kab uas hla ntawm cov tub ntxhais kawm nkag.
Qhov parameter no tseem ceeb kom paub txog thaum tua nrog a lub koob yees duab, raws li nws cuam tshuam rau lub teeb uas dhau los ntawm lub lens. Qhov loj dua tus naj npawb F-Stop, qhov me dua qhov qhib aperture, thiab yog li qhov tsawg lub teeb uas tso cai rau hauv.
Kab lus no yuav tshawb txog lub tswvyim ntawm F-Stop kom ntxaws ntxiv thiab piav qhia vim li cas thiaj tseem ceeb kom nkag siab thaum tua.
Hauv kab ntawv no peb yuav npog:
F-Stop yog dab tsi?
F-Nres (Kuj hu ua focal ratio) yog ib feem ntawm kev yees duab uas muaj feem xyuam rau lub teeb ntawm lub lens tuaj yeem sau tau, lossis nws lub peev xwm los txo qhov loj ntawm qhov aperture. Nws yog ntsuas raws li qhov sib piv ntawm lub lens 'kev nkag mus rau cov tub ntxhais kawm qhov loj thiab qhov focal ntev, thiab txhais los ntawm tus lej ua raws li qhov f, Xws li f / 2.8. Qhov tsawg dua tus lej no, qhov loj ntawm cov tub ntxhais kawm nkag, ua rau muaj teeb pom kev nkag tau ntau dua. Hloov pauv, muaj tus lej f-stop loj yuav txhais tau tias lub teeb tsawg dua tuaj yeem nkag los ntawm koj lub lens thiab aperture.
F-Stop kuj tseem ua haujlwm hauv tes nrog shutter ceev; thaum koj paub ib yam koj yuav tau yooj yim xam rau lwm yam. Nws tseem muaj txiaj ntsig zoo rau kev tsom mus rau cov khoom ze zoo li portraits los ntawm kev nce koj tus lej f-stop thiab tso cai rau kev tswj xyuas kom pom tseeb ntawm koj qhov kev txhaj tshuaj; qhov no suav nrog txhua hom kev yees duab los ntawm cov tsiaj qus mus rau qhov kev yees duab, tab sis tseem ceeb dua hauv kev yees duab portrait uas cov keeb kwm yav dhau yuav tsum tau ua kom pom tseeb txhawm rau tsom ntsoov rau koj qhov kev kawm. Tus naj npawb f-stop loj dua tso cai rau tom qab qhov muag plooj ntau dua thiab ua kom pom tseeb zoo dua ntawm kev nyob ze lossis qhov tob tob ntawm qhov chaw txhaj tshuaj.
Tag nrho lo ntsiab muag muaj cov yam ntxwv sib txawv uas cuam tshuam rau lawv lub peev xwm f / tus lej; vim qhov no koj yuav xav tau ntau lub lo ntsiab muag kom haum rau koj cov kev xav tau tshwj xeeb thaum thaij duab lossis yeeb yaj kiab. Focal ratio kuj ua hauj lwm txawv nyob ntawm seb qhov loj ntawm sensor; Cov koob yees duab tag nrho feem ntau muaj qhov tob tob ntawm thaj teb ntau dua li cov koob yees duab cropped vim lawv qhov loj dua sensor loj-lub ntsiab lus ntau dua ntawm cov khoom txhawm rau kom cov khoom no nyob twj ywm hauv kev tsom ib zaug hauv koj lub thav duab. To taub li cas Focal Ratios tuaj yeem cuam tshuam koj lub koob yees duab lub peev xwm tuaj yeem pab koj txiav txim siab txog cov lo ntsiab muag twg zoo tshaj plaws rau ntau yam haujlwm nrog rau yuav ua li cas lawv tuaj yeem cuam tshuam tag nrho qhov zoo thaum ua haujlwm nrog cov haujlwm sib txawv lossis cov xwm txheej tua.
Focal Ratio yog dab tsi?
Focal piv, feem ntau hais txog f-nres, yog qhov chaw kaw qhov ceev uas tau hais tseg nyob rau hauv cov nqe lus ntawm cov nres lossis qhov loj ntawm lub lens qhib tsim los ntawm lub lens. Tus lej loj dua, qhov me me ntawm lub lens qhib thiab lub teeb tsawg dua uas ncav cuag koj lub koob yees duab sensor. Nws feem ntau yog los ntawm f/1.4 rau f/32 rau feem ntau lo ntsiab muag tab sis tuaj yeem mus ntau dua yog tias koj xav tau ntes lub teeb ntawm qhov deb.
Focal piv Nws yog ib qho tseem ceeb vim tias nws tswj tau ntau npaum li cas lub teeb ncav cuag koj lub koob yees duab lub sensor, tso cai rau koj los ntes cov duab pom zoo yam tsis muaj tshaj lossis qis dua. Tus lej qis dua muab qhov tob tob rau koj thaum qhov siab dua yuav ua rau koj qhov tob dua thiab ua kom pom tseeb ntawm cov khoom nyob deb. Lub kaw lus qeeb qeeb yuav tsum tau f-stop ntau dua thaum lub kaw lus nrawm yuav tsum tau f-stop tsawg dua; yog li kev tua nrog ntau lub teeb yuav tsum tsawg f-nres thaum tua hauv lub teeb qis yuav tsum tau ntau dua li ib qho F8 los yog qis dua nrog rau qhov tsim nyog ISO. Qhov nce sharpness thaum nres (qis koj F-Stop) kuj ntxiv rau tag nrho cov duab sharpness.
Thaum hloov koj lub F-Stop, nco ntsoov tias txhua qhov nce lossis nqis sib raug rau qhov kev hloov pauv ntawm qhov chaw nres tsheb (sib npaug rau ob npaug lossis ib nrab ntawm lub teeb). Nrog rau qhov kev nkag siab no, ib tus tuaj yeem hloov kho lawv qhov sib piv raws li qhov xav tau raug pom zoo nrog rau qhov xav tau qhov tob ntawm qhov cuam tshuam rau lawv cov phiaj xwm kev yees duab.
Nkag siab F-Stop
F-nres, kuj hu ua focal ratio, yog lub tswv yim tseem ceeb hauv kev yees duab thiab yees duab, uas ua lub luag haujlwm loj hauv koj cov duab li cas. F-stop yog qhov sib piv ntawm lub lens focal ntev thiab txoj kab uas hla ntawm tus tub kawm ntawv nkag. Nws yog qhia raws li tus naj npawb, thiab tuaj yeem muaj los ntawm qhov qis ntawm f/1.4 mus txog f/32 los yog siab dua. Nkag siab txog F-stop yog qhov tseem ceeb rau txhua tus uas tab tom nrhiav kom tau txais cov duab zoo dua.
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F-Stop cuam tshuam li cas rau qhov raug?
Thaum tus kws yees duab kho qhov aperture (F-Nres) ntawm ib lub lens, lawv ncaj qha cuam tshuam npaum li cas lub teeb nkag mus rau hauv lub lens thiab sensor. Qhov qis F-Stop tso cai rau lub teeb kom ntau dua thaum tus lej F siab dua txwv nws. Los ntawm kev qhib lub aperture nrog qis F-Stop, koj tsim qhov dav dav ntawm kev ua kom pom tseeb uas tso cai rau ntau lub teeb nkag mus thiab pab tsim qhov tob tob ntawm qhov chaw uas qiv nws tus kheej zoo rau portraiture lossis ib qho duab uas xav tau cov txheej txheem ntiav thiab sib cais. Tsis tas li ntawd, qhov no tuaj yeem muaj txiaj ntsig zoo hauv cov xwm txheej qis uas tsis muaj lub teeb txaus kom nthuav tawm cov ncej kom zoo.
Kev hu xov tooj rau hauv qhov tsim nyog F-Stop rau qhov xwm txheej tseem cuam tshuam ncaj qha rau lub sijhawm raug, uas tuaj yeem hloov kho los ntawm kev kaw nrawm ntawm ntau lub koob yees duab thaum teeb tsa rau hom kev tuav. Txhawm rau kom koj lub hom phiaj keeb kwm yav dhau los lossis cov ntsiab lus tseem ceeb, txo koj lub sijhawm kaw thiab kho koj lub aperture kom haum rau koj cov duab kom raug rau lub sijhawm zoo meej - thiab tsis txhob hnov qab txog Kev hloov kho ISO zoo li!
Lub tswvyim dav dua tom qab f/stop yog qhov ntawd ntsuas aperture thiab shutter ceev yog qhov tseem ceeb ntawm kev yees duab zoo; ob qho tib si cuam tshuam ntev npaum li cas lub koob yees duab sensor raug rau lub teeb tuaj. Thaum tua hauv Phau Ntawv Qhia, koj yuav tsum xav txog tag nrho peb yam thaum sim kom tau txais cov duab pom zoo kawg nkaus:
- Kev teeb tsa ISO (los yog zaj duab xis rhiab heev)
- kaw hluav taws xob
- f/stop/aperture rau framing variables xws li qhov tob ntawm kev tswj teb los yog motion blur attribute imagery.
Kev sib raug zoo ntawm F-Stop thiab Focal Ratio yog dab tsi?
F-Nres yog qhov piv ntawm lub lens lub focal ntev rau nws txoj kab uas hla. Qhov siab dua F-Stop, qhov me me ntawm qhov aperture thiab qhov tob ntawm qhov chaw ntau dua hauv ib daim duab. F-Stop yog siv los txiav txim siab npaum li cas lub teeb mus txog lub koob yees duab sensor nrog rau qhov dav lossis nqaim qhov qhib rau ntawm lub lens muab.
Focal Ratio, los yog f / nres luv luv, tuaj yeem xav tias yog ib nrab ntawm cov npe uas qhia koj txog koj lub koob yees duab thiab lens ua ke. Thaum xa mus rau f-stop hauv kev yees duab, nws feem ntau cuam tshuam rau qhov chaw aperture. Ib yam li shutter ceev, qhov chaw aperture tuaj yeem hloov kho lub teeb uas dhau los ntawm koj lub lo ntsiab muag thiab ua rau nws txoj hauv kev mus rau koj cov duab sensor (lossis zaj duab xis). qis tus lej f nres yuav tsim lub teeb ntau dua thaum cov lej ntau dua txo lub teeb hla dhau. Yog li ntawd, qis tus lej nres yuav tsim cov duab ci dua nrog qhov tob tob ntawm qhov chaw thaum cov lej ntau dua ua rau cov duab tsaus nrog ntau qhov ua kom pom tseeb lossis qhov tob ntawm qhov chaw (Related: Dab tsi yog qhov tob ntawm Field?).
Lwm qhov hauv daim ntawv no yog hu ua "focal ntev"uas tsuas yog txhais tau tias"deb” Qhov no txhais tau tias nyob ze lossis deb npaum li cas koj tuaj yeem tsom mus rau ib qho kev kawm - zoo li cov koob yees duab lo ntsiab muag qhov ntau thiab tsawg tau piav qhia hauv kab lus no (Related: Nkag siab lub koob yees duab Lenses Sizes). Cov lo ntsiab muag niaj hnub no feem ntau yog cov lo ntsiab muag zoom txhais tau tias lawv muaj qhov ntev focal adjustable yog li koj tuaj yeem nyob ze lossis deb ntawm koj qhov kev kawm yam tsis tas yuav txav mus los ntawm koj tus kheej.
Yog li dab tsi raws nraim yuav tshwm sim thaum koj kho koj F-nres? Raws li tau hais los saum toj no nws hais txog ntau npaum li cas lub teeb dhau los ntawm koj lub lens yog li qhov tseem ceeb thaum koj kho nws qhov koj tab tom ua yog kev hloov kho ntawm qhov siab tshaj plaws thiab qhov tob ntawm qhov chaw muaj rau kev txhaj tshuaj. Nrog cov lej qis tso cai rau lub teeb ntau dua rau qhov ci dua tab sis qhov muag plooj thiab cov lej ntau dua muab qhov tsaus tab sis ntse dua. Tias yog vim li cas kev ua si ib puag ncig nrog xws li kev teeb tsa hauv kev yees duab tuaj yeem cuam tshuam qhov cuam tshuam ntau ntxiv nrog rau kev ua kom pom tseeb hauv ib qho kev sib xyaw - yog li vim li cas thiaj paub txog F-Stops thiab focal ratios yuav tsum nco ntsoov coj mus rau hauv kev xav ua ntej thaij duab!
Nkag siab Focal Ratio
F-Nres, thiaj li lub npe hu ua lub focal ratio, yog lub tswv yim tseem ceeb hauv kev yees duab uas hais txog qhov loj ntawm qhov aperture ntawm lub koob yees duab lens. Nws yog ib feem uas ib txwm sau ua tus lej, xws li f/2.8 los yog f/5.6.
To taub lub tswvyim ntawm F-Nres Nws yog ib qho tseem ceeb rau cov kws yees duab vim tias nws yuav pab lawv paub tias lawv xav tau lub teeb npaum li cas kom pom cov duab kom raug. Tsis tas li ntawd, nws tseem cuam tshuam rau tob ntawm daim teb, uas yog qhov ntau ntawm cov duab uas nyob rau hauv tsom. Cia peb dhia dej tob me ntsis thiab kawm ntxiv txog F-Nres thiab nws qhov tseem ceeb.
Dab tsi yog qhov kev sib raug zoo ntawm Focal Ratio thiab qhov kev pom?
Thaum thaij duab, lub focal ratio - nquag hu ua f-nres - yog ib qho tseem ceeb tshaj plaws los xav txog. Nws yog siv los tswj qhov loj ntawm daim duab teb ntawm saib, lossis ntau npaum li cas ntawm ib qho chaw koj tuaj yeem ntes tau hauv kev txhaj tshuaj. Tus lej f-stop ntau dua yuav tsim cov duab dav dua, thaum tus lej qis dua yuav tsim cov duab nrog txwv qhov tob ntawm thaj teb.
Lub focal ratio kuj cuam tshuam rau tob ntawm daim teb hauv koj daim duab lossis yees duab thaum siv nrog cov lo ntsiab muag sib txawv. Thaum tua ntawm qhov dav aperture (tsawg f-stop), nws ua rau qhov tob tob heev. Hloov pauv, siv cov f-stops siab yuav tsim qhov tob dua tab sis tuaj yeem ua rau qee qhov tsis meej pem hauv qab thiab pem hauv ntej thaj chaw vim muaj ntau qhov sib txawv ntawm qhov chaw me me ntawm koj tus ncej.
Kev sib raug zoo ntawm focal ratio thiab thaj tsam ntawm kev pom yog qhov tseeb; nws tsuas yog tias siab dua f-stops tsim cov duab nqaim thiab rov ua dua. Qhov no txhais tau hais tias thaum tua toj roob hauv pes lossis lwm qhov chaw loj nrog cov ntsiab lus nyob deb, koj yuav xav tau lub lens dav dav (nrog rau qhov tsim nyog qis f-stop) lossis koj tuaj yeem siv ntau lub lo ntsiab muag ntawm qhov sib txawv focal ratios kom tau txais kev sib xyaw kom haum rau kev ntes. txhua yam ntawm koj qhov kev kawm.
Focal Ratio cuam tshuam li cas rau qhov tob ntawm daim teb?
Focal ratio (kuj paub zoo li tus f-nres) yog ib qho ntawm cov yam ntxwv tseem ceeb hauv kev yees duab, feem ntau suav nrog 'f/' nyob rau hauv pem hauv ntej ntawm tus lej. Hauv particular, qhov focal ratio muaj feem xyuam rau qhov tob ntawm thaj tsam thiab raug cuam tshuam uas tuaj yeem cuam tshuam cov txiaj ntsig ntawm koj cov duab.
Qhov tob ntawm qhov chaw hais txog ntau npaum li cas ntawm ib qho xwm txheej tshwm sim hauv kev tsom. A qhov tob ntiav ntawm teb yog ib qho uas tsuas yog ib feem ntawm ib qho kev tshwm sim hauv kev tsom xam thaum a dav dav ntawm qhov chaw yog ib qho uas txhua yam zoo li ntse. Cov focal ratio plays lub luag haujlwm tseem ceeb hauv kev txiav txim siab qhov tob uas suav nrog hauv ib daim duab.
Ib tug loj focal ratio (piv txwv li, f / 11) pub rau a dav dav ntawm qhov chaw uas suav nrog ob qho tib si nyob ze thiab deb thiab txhua yam ntawm lawv. Hom kev teeb tsa no yuav ua haujlwm zoo tshaj plaws rau cov duab toj roob hauv pes lossis sab nraum zoov cov duab uas yuav tsum tau suav nrog ob qho tib si foreground thiab keeb kwm yav dhau los nrog ntau dua sharpness thiab clarity. Vim li no, ntau tus kws yees duab tshaj lij nyiam xaiv f-nres loj dua rau kev txhaj tshuaj sab nrauv.
Txawm li cas los xij, thaum tua cov ntsiab lus ze dua - xws li portrait photography los yog macro photography - nws yuav tsim nyog ua kom siv me me focal ratios (xws li f/1.4). Cov chaw no tso cai rau qhov tob tob uas pab cais cov ntsiab lus los ntawm nws keeb kwm yav dhau, tsim kom muaj txiaj ntsig zoo thiab muaj txiaj ntsig nrog cov ntsiab lus zoo nkauj cais rau hauv kev tsom xam ntawm qhov muag tsis pom ib puag ncig.
xaus
F-nres or focal ratio yog ib lub tswv yim tseem ceeb rau cov kws yees duab kom nkag siab. Nws pab piav qhia txog ntau yam ntawm cov txiaj ntsig aperture, thiab tob ntawm daim teb. Kev nkag siab txog lub tswv yim no pab kom nkag siab txog kev siv cov lo ntsiab muag sib txawv thiab cov koob yees duab kom tau txais cov txiaj ntsig xav tau. Tsis tas li ntawd, nws tseem pab kom paub tseeb tias koj tau txais cov duab koj xav tau los ntawm kev tswj cov teeb pom kev nkag mus rau lub koob yees duab.
Los xaus, nws yog ib qho tseem ceeb rau cov kws yees duab kom nkag siab txog lub tswv yim ntawm f-nres or focal ratio kom paub tseeb tias lawv cov duab zoo meej.
Vim li cas F-Stop thiab Focal Ratio tseem ceeb rau cov kws yees duab?
Rau cov kws yees duab, lub f-nres thiab focal ratio yog cov ntsiab lus tseem ceeb ntawm kev nkag siab qhov raug, lens sharpness thiab bokeh. Cov focal ratio hais txog qhov loj ntawm lub lens qhib, los yog aperture, uas pab txiav txim siab npaum li cas lub teeb tso cai los ntawm lub lens kom ncav cuag lub koob yees duab sensor. Thaum tus kws yees duab hloov qhov loj ntawm lub aperture los ntawm kev siv txawv f- nres, nws yuav cuam tshuam rau lawv cov duab tau tob ntawm daim teb.
Ib qhov loj dua f-nres tus lej yuav tsim ib tug me me aperture ua rau ntau dua qhov tob ntawm teb nrog ntau nyob rau hauv tsom xam - qhov no yuav yog ib tug zoo chaw rau duab toj roob hauv pes yog li koj tau txais txhua yam hauv kev tsom. Tus lej me me yuav muab rau koj aperture loj dua thiab qhov tob tob ntawm qhov ua rau koj cov ntsiab lus sawv tawm ntau dua - qhov no yuav yog qhov zoo tshaj rau duab thaij duab qhov twg koj xav kom plooj ntawm ob sab ntawm koj cov duab portrait.
Ntxiv nrog rau kev pab tswj kev raug mob, F-stop thiab Focal Ratio kuj tseem muaj qhov cuam tshuam rau qhov ntse thaum siv lo ntsiab muag nrog kev daws teeb meem tsawg; siv lub aperture nqaim (siab dua f-stop) tuaj yeem pab txo qee qhov muag vim qhov txawv txav thiab vignetting. Los ntawm kev nkag siab txog ob qhov tseem ceeb no, tus kws yees duab tuaj yeem ua tau zoo kho lawv lub koob yees duab qhov chaw raws li shooting tej yam kev mob nyob rau hauv thiaj li yuav ua kom cov duab zoo, teeb tsa cov duab raug pom tseeb hauv cov teeb pom kev nyuaj thiab ua tiav qhov kev xav tau zoo los ntawm kev tswj qhov tob ntawm qhov chaw thaum ua haujlwm nrog primes lossis zooms muaj kev daws teeb meem tsawg.
Koj xaiv qhov F-Stop thiab Focal Ratio li cas rau koj cov duab?
Xaiv qhov tseeb F-Stop thiab Focal Ratio rau koj qhov kev yees duab yog qhov kev ntsuas tseem ceeb ntawm kev ua tiav. Cov teebmeem ntawm cov lo ntsiab muag ntawm koj cov duab yuav raug txiav txim siab los ntawm qhov koj tau teeb tsa rau lawv thaum koj xaiv qhov xav tau shutter ceev thiab aperature.
Ua ntej, koj yuav tsum tshuaj xyuas qhov xav tau tob ntawm daim teb koj npaj kom ua tiav hauv koj daim duab. Yog xav tau qhov tob tob ntawm qhov chaw, ces me F-Stops xws li f/2 los yog f/2.8 yuav tsum tau saws. Ntawm qhov tod tes, yog tias nws yog ntshaw kom ntes tau ntau tus lej nrog qhov sib npaug ntawm qhov tseeb ces ntau dua tus lej F-Stops xws li f/5 rau f/22 yuav tsum siv xwb.
Nws yog tsim nyog sau cia tias txij li cov lo ntsiab muag ceev yuav raug nqi ntau dua li cov lo ntsiab muag qeeb, ib tus yuav tsum tau them nyiaj ntxiv rau lawv cov peev nyiaj thaum xaiv qhov kev kaw nrawm nrawm nrog rau qhov sib txawv kuj saib xyuas seb lawv xav tau lub teeb npaum li cas thaum sim nrog lawv qhov aperture chaw. Nws kuj tseem yuav yog qhov zoo rau xa mus rau cov neeg siv phau ntawv lossis cov kev qhia hauv online uas piav qhia seb hom lens twg thiab cov teeb tsa zoo tshaj plaws rau txhua qhov xwm txheej txhawm rau txhawm rau ua tiav cov kev ntsuas no dhau sijhawm. Txawm li cas los xij, tsis muaj lus teb meej thiab nkag siab koj tus kheej nyiam los ntawm kev sim yuav pab ua kom zoo rau kev kos duab kom tau txais cov duab zoo nyob rau lub sijhawm!
Nyob zoo, Kuv yog Kim, niam thiab ib tus neeg nyiam nres nrog keeb kwm yav dhau los hauv kev tshaj tawm thiab kev txhim kho lub vev xaib. Kuv muaj kev mob siab rau kev kos duab thiab kev ua yeeb yam, thiab tam sim no kuv tab tom dhia taub hau ua ntej mus rau hauv lub ntiaj teb nres. Nrog rau kuv qhov blog, Kuv tabtom qhia kuv cov kev kawm nrog koj.
