Txhim kho koj tus yees duab los ntawm kev xaiv txoj kev lens
Focal ntev yog lub ntsiab lus tseem ceeb ntawm kev yees duab thiab hauv nws cov lus piav qhia yooj yim nws yog qhov kev pom ntawm ib lub koob yees duab lens.
Lub focal ntev txiav txim siab npaum li cas ntawm ib tug scene lub koob yees duab pom. Nws yuav txawv ntawm ntau cov ces kaum uas yuav siv tau rau tag nrho cov toj roob hauv pes rau telephoto lo ntsiab muag uas tuaj yeem txuam rau hauv ib qho kev kawm me me nyob deb.
Thaum shooting nrog txhua lub koob yees duab, tab sis tshwj xeeb tshaj yog lub koob yees duab DSLR , nws yog ib qho tseem ceeb kom muaj kev nkag siab zoo ntawm focal ntev. Muaj qee cov kev paub yooj yim, koj tuaj yeem xaiv qhov zoo ntawm lub lens rau ib qho kev kawm thiab yuav paub tias dab tsi yuav tau txais txawm tias ua ntej koj yuav pom los ntawm qhov pom kev .
Tsab xov xwm no yuav pab koj to taub qhov ntev ntawm qhov focal thiab piav qhia qhov tseem ceeb ntawm qhov focal length nyob hauv digital photography.
Qhov chaw nyob ntev npaum li cas?
Ntawm no yog qhov kev txhais ntawm focal ntev: Thaum uas tig mus sab nrauv ntawm lub teeb tsom ib lub lens tsom rau ntawm infinity, lawv sib dhos los ua ib qho taw tes. Lub focal ntev ntawm lub lens yog qhov deb ntawm nruab nrab ntawm lub lens mus rau qhov chaw no.
Lub focal ntev ntawm lub lens yuav tshwm rau ntawm lub thoob ntawm lub lens.
Hom Lenses
Lo ntsiab muag feem ntau categorized li wide-angle, txheem (los yog ib txwm), los yog telephoto . Lub focal ntev ntawm lub lens txiav txim siab lub kaum sab xis ntawm qhov pom, yog li qhov laj thawj wide-angle muaj qhov ntev me me thaum lub xov tooj lithos muaj qhov loj focal ntev.
Ntawm no yog ib daim ntawv teev npe ntawm lub meej focal ntev txhais hauv txhua qeb ntawm lens:
- Tsawg tshaj 21 hli: Super wide-angle lens
- 21-35mm: Lens-wide lens
- 35-70mm: Txuj / Lens qes
- 70-135mm: Txheem Telephoto
- 135-300mm (los yog ntau tshaj): Telephoto
Zoom vs Prime lo ntsiab muag
Muaj ob hom kev lo lo ntsiab muag: prime (los yog tsau) thiab zoom.
- Ib lub lens lens yuav muaj tsuas yog ib qhov ntev ntawm focal (piv txwv li 50 hli).
- Lub zoom lens yuav them rau ib chav ntawm cov focal ntev (xws li 17-40mm).
Zoom Lens Zoo Tshaj Plaws
Zoom tsom iav yooj yim vim tias koj tuaj yeem hloov pauv cov focal ntev thaum saib ntawm qhov pom thiab koj tsis tas yuav nqa lub koob yees duab hnab puv ntawm lo ntsiab muag. Feem ntau cov amateur cov kev pabcuam tuaj yeem tau txais los ntawm ib lossis ob qhov muag lo ntsiab muag uas khwb tag nrho cov focal ntev.
Ib qho uas yuav tsum xav txog, txawm li cas los, yog qhov loj ntawm qhov koj xav tau hauv ib qho lens zoom. Muaj ntau lo ntsiab muag uas mus los ntawm 24 mus txog 300 hli (thiab nyob qhov twg hauv nruab nrab) thiab cov no yog yooj yim heev.
Qhov teeb meem yog feem ntau qhov zoo ntawm iav hauv cov lo ntsiab muag no vim yog qhov dav qhov ntau, qhov hais ntxiv ntawm lub teeb muaj mus los ntawm. Yog hais tias koj nyiam nyob rau hauv ib qho ntawm cov khom dynamic qhov lo ntsiab muag thiab xav tau qhov zoo tshaj plaws daim duab zoo, nws yuav zoo tshaj yog siv nyiaj ntau dua rau saum lub lens zoo.
Prime Lens Advantages
Prime lo ntsiab muag muaj ob lub ntsiab qhov tseem ceeb: zoo thiab ceev.
Los ntawm kev ceev, peb tab tom tham txog qhov nthuav dav tshaj plaws (f / nres) ua rau hauv lub lens. Nyob rau ntawm lub qis aperture (tsawg dua, qhib dav hlau), koj tuaj yeem thaij duab qis dua thiab siv ceev ceev ceev uas yuav nres. Qhov no yog vim li cas f / 1.8 yog lub qhov qhib qhov luaj li cas hauv lo ntsiab muag. Zoom tsom iav tsis tshua tau qhov no sai thiab yog tias lawv ua, lawv yeej kim heev.
Lub lens prime yog ib qho yooj yim dua hauv txoj kev tsim dua lub lens zoom vim muaj tsawg dua cov iav hauv sab hauv lub thawv thiab lawv tsis tas yuav txav mus rau hauv focal ntev. Tsawg iav mus ncig los ntawm txhais tau hais tias tsis tshua muaj caij nyoog rau distortion thiab qhov no feem ntau muab cov duab ntxoo kom pom tseeb thiab meej meej.
Focal Length Magnifier
Lub focal ntev ntawm lo ntsiab muag twb teem rov qab rau hauv lub hnub ntawm zaj duab xis photography thiab koom rau lub focal ntev ntawm ib lub lens ntawm ib lub koob yees duab 35mm. (Nco ntsoov, tias, 35mm hais txog hom yeeb yaj kiab uas siv thiab tsis ntev npaum li cas focal!) Yog tias koj muaj hmoo txaus los muaj ib tus neeg ua haujlwm full-frame DSLR, ces koj lub focal ntev yuav tsis zoo.
Yog tias, txawm li cas los xij, koj siv ib lub voj qoob (APS-C) lub koob yees duab, ces koj lub focal ntev yuav raug cuam tshuam. Vim tias cov qoob loo ntawm cov qoob loo muaj zog tshaj li ntawm 35 hli sawb ntawm zaj duab xis, magnification yuav tsum muaj ntaub ntawv. Qhov loj tuaj nws txawv me ntsis ntawm cov tuam ntxhab, tab sis tus qauv yog x1.6. Canon siv qhov kev loj hlob no, tab sis Nikon siv x1.5 thiab Olympus siv x 2.
Piv txwv, ntawm Canon crop frame camera, tus txheem 50mm lens tiav ib tug qauv telephoto 80mm lens. (50 hli multiplied los ntawm ib yam ntawm 1.6 kom tshwm sim rau hauv 80mm.)
Feem ntau cov tuam ntxhab tam sim no ua lo ntsiab muag uas cia rau qhov kev cia siab no, uas tsuas yog ua haujlwm ntawm cov koob thaav duab. Qhov no yog qhov tseem ceeb tshaj plaws ntawm qhov dav-qhov kawg ntawm cov khoom, qhov loj qhov tuaj yeem tig cov lens no rau hauv tus qauv!